From d19fbc3c171aa71a79b2ff0b654e3064c91628b8 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 7 Jan 2007 19:23:49 -0500 Subject: Documentation: add git user's manual The goals are: - Readable from beginning to end in order without having read any other git documentation beforehand. - Helpful section names and cross-references, so it's not too hard to skip around some if you need to. - Organized to allow it to grow much larger (unlike the tutorials) It's more liesurely than tutorial.txt, but tries to stay focused on practical how-to stuff. It adds a discussion of how to resolve merge conflicts, and partial instructions on setting up and dealing with a public repository. I've lifted a little bit from "branching and merging" (e.g., some of the discussion of history diagrams), and could probably steal more if that's OK. (Similarly anyone should of course feel free to reuse bits of this if any parts seem more useful than the whole.) There's a lot of detail on managing branches and using git-fetch, just because those are essential even to people needing read-only access (e.g., kernel testers). I think those sections will be much shorter once the new "git remote" command and the disconnected checkouts are taken into account. I do feel bad about adding yet another piece of documentation, but I we need something that goes through all the basics in a logical order, and I wasn't seeing how to grow the tutorials into that. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/Makefile b/Documentation/Makefile index 93c7024..c2ee5b4 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -17,7 +17,7 @@ ARTICLES += hooks ARTICLES += everyday ARTICLES += git-tools # with their own formatting rules. -SP_ARTICLES = glossary howto/revert-branch-rebase +SP_ARTICLES = glossary howto/revert-branch-rebase user-manual DOC_HTML += $(patsubst %,%.html,$(ARTICLES) $(SP_ARTICLES)) @@ -89,6 +89,12 @@ clean: %.xml : %.txt asciidoc -b docbook -d manpage -f asciidoc.conf $< +user-manual.xml: user-manual.txt user-manual.conf + asciidoc -b docbook -d book $< + +user-manual.html: user-manual.xml + xmlto -m /etc/asciidoc/docbook-xsl/xhtml.xsl html-nochunks $< + git.html: git.txt README glossary.html : glossary.txt sort_glossary.pl diff --git a/Documentation/docbook-xsl.css b/Documentation/docbook-xsl.css new file mode 100644 index 0000000..8821e30 --- /dev/null +++ b/Documentation/docbook-xsl.css @@ -0,0 +1,286 @@ +/* + CSS stylesheet for XHTML produced by DocBook XSL stylesheets. + Tested with XSL stylesheets 1.61.2, 1.67.2 +*/ + +span.strong { + font-weight: bold; +} + +body blockquote { + margin-top: .75em; + line-height: 1.5; + margin-bottom: .75em; +} + +html body { + margin: 1em 5% 1em 5%; + line-height: 1.2; +} + +body div { + margin: 0; +} + +h1, h2, h3, h4, h5, h6, +div.toc p b, +div.list-of-figures p b, +div.list-of-tables p b, +div.abstract p.title +{ + color: #527bbd; + font-family: tahoma, verdana, sans-serif; +} + +div.toc p:first-child, +div.list-of-figures p:first-child, +div.list-of-tables p:first-child, +div.example p.title +{ + margin-bottom: 0.2em; +} + +body h1 { + margin: .0em 0 0 -4%; + line-height: 1.3; + border-bottom: 2px solid silver; +} + +body h2 { + margin: 0.5em 0 0 -4%; + line-height: 1.3; + border-bottom: 2px solid silver; +} + +body h3 { + margin: .8em 0 0 -3%; + line-height: 1.3; +} + +body h4 { + margin: .8em 0 0 -3%; + line-height: 1.3; +} + +body h5 { + margin: .8em 0 0 -2%; + line-height: 1.3; +} + +body h6 { + margin: .8em 0 0 -1%; + line-height: 1.3; +} + +body hr { + border: none; /* Broken on IE6 */ +} +div.footnotes hr { + border: 1px solid silver; +} + +div.navheader th, div.navheader td, div.navfooter td { + font-family: sans-serif; + font-size: 0.9em; + font-weight: bold; + color: #527bbd; +} +div.navheader img, div.navfooter img { + border-style: none; +} +div.navheader a, div.navfooter a { + font-weight: normal; +} +div.navfooter hr { + border: 1px solid silver; +} + +body td { + line-height: 1.2 +} + +body th { + line-height: 1.2; +} + +ol { + line-height: 1.2; +} + +ul, body dir, body menu { + line-height: 1.2; +} + +html { + margin: 0; + padding: 0; +} + +body h1, body h2, body h3, body h4, body h5, body h6 { + margin-left: 0 +} + +body pre { + margin: 0.5em 10% 0.5em 1em; + line-height: 1.0; + color: navy; +} + +tt.literal, code.literal { + color: navy; +} + +div.literallayout p { + padding: 0em; + margin: 0em; +} + +div.literallayout { + font-family: monospace; +# margin: 0.5em 10% 0.5em 1em; + margin: 0em; + color: navy; + border: 1px solid silver; + background: #f4f4f4; + padding: 0.5em; +} + +.programlisting, .screen { + border: 1px solid silver; + background: #f4f4f4; + margin: 0.5em 10% 0.5em 0; + padding: 0.5em 1em; +} + +div.sidebar { + background: #ffffee; + margin: 1.0em 10% 0.5em 0; + padding: 0.5em 1em; + border: 1px solid silver; +} +div.sidebar * { padding: 0; } +div.sidebar div { margin: 0; } +div.sidebar p.title { + font-family: sans-serif; + margin-top: 0.5em; + margin-bottom: 0.2em; +} + +div.bibliomixed { + margin: 0.5em 5% 0.5em 1em; +} + +div.glossary dt { + font-weight: bold; +} +div.glossary dd p { + margin-top: 0.2em; +} + +dl { + margin: .8em 0; + line-height: 1.2; +} + +dt { + margin-top: 0.5em; +} + +dt span.term { + font-style: italic; +} + +div.variablelist dd p { + margin-top: 0; +} + +div.itemizedlist li, div.orderedlist li { + margin-left: -0.8em; + margin-top: 0.5em; +} + +ul, ol { + list-style-position: outside; +} + +div.sidebar ul, div.sidebar ol { + margin-left: 2.8em; +} + +div.itemizedlist p.title, +div.orderedlist p.title, +div.variablelist p.title +{ + margin-bottom: -0.8em; +} + +div.revhistory table { + border-collapse: collapse; + border: none; +} +div.revhistory th { + border: none; + color: #527bbd; + font-family: tahoma, verdana, sans-serif; +} +div.revhistory td { + border: 1px solid silver; +} + +/* Keep TOC and index lines close together. */ +div.toc dl, div.toc dt, +div.list-of-figures dl, div.list-of-figures dt, +div.list-of-tables dl, div.list-of-tables dt, +div.indexdiv dl, div.indexdiv dt +{ + line-height: normal; + margin-top: 0; + margin-bottom: 0; +} + +/* + Table styling does not work because of overriding attributes in + generated HTML. +*/ +div.table table, +div.informaltable table +{ + margin-left: 0; + margin-right: 5%; + margin-bottom: 0.8em; +} +div.informaltable table +{ + margin-top: 0.4em +} +div.table thead, +div.table tfoot, +div.table tbody, +div.informaltable thead, +div.informaltable tfoot, +div.informaltable tbody +{ + /* No effect in IE6. */ + border-top: 2px solid #527bbd; + border-bottom: 2px solid #527bbd; +} +div.table thead, div.table tfoot, +div.informaltable thead, div.informaltable tfoot +{ + font-weight: bold; +} + +div.mediaobject img { + border: 1px solid silver; + margin-bottom: 0.8em; +} +div.figure p.title, +div.table p.title +{ + margin-top: 1em; + margin-bottom: 0.4em; +} + +@media print { + div.navheader, div.navfooter { display: none; } +} diff --git a/Documentation/user-manual.conf b/Documentation/user-manual.conf new file mode 100644 index 0000000..92b01ecf --- /dev/null +++ b/Documentation/user-manual.conf @@ -0,0 +1,21 @@ +[titles] + underlines="__","==","--","~~","^^" + +[attributes] +caret=^ +startsb=[ +endsb=] +tilde=~ + +[gitlink-inlinemacro] +{target}{0?({0})} + +ifdef::backend-docbook[] +# "unbreak" docbook-xsl v1.68 for manpages. v1.69 works with or without this. +[listingblock] +{title} + +| + +{title#} +endif::backend-docbook[] diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt new file mode 100644 index 0000000..30ad103 --- /dev/null +++ b/Documentation/user-manual.txt @@ -0,0 +1,1460 @@ +Git User's Manual +_________________ + +This manual is designed to be readable by someone with basic unix +commandline skills, but no previous knowledge of git. + +Comprehensive reference documentation is available through the man +pages. For a command such as "git clone", just use + +------------------------------------------------ +$ man git-clone +------------------------------------------------ + +Repositories and Branches +========================= + +How to get a git repository +--------------------------- + +It will be useful to have a git repository to experiment with as you +read this manual. + +The best way to get one is by using the gitlink:git-clone[1] command +to download a copy of an existing repository for a project that you +are interested in. If you don't already have a project in mind, here +are some interesting examples: + +------------------------------------------------ + # git itself (approx. 10MB download): +$ git clone git://git.kernel.org/pub/scm/git/git.git + # the linux kernel (approx. 150MB download): +$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git +------------------------------------------------ + +The initial clone may be time-consuming for a large project, but you +will only need to clone once. + +The clone command creates a new directory named after the project +("git" or "linux-2.6" in the examples above). After you cd into this +directory, you will see that it contains a copy of the project files, +together with a special top-level directory named ".git", which +contains all the information about the history of the project. + +In the following, examples will be taken from one of the two +repositories above. + +How to check out a different version of a project +------------------------------------------------- + +Git is best thought of as a tool for storing the history of a +collection of files. It stores the history as a compressed +collection of interrelated snapshots (versions) of the project's +contents. + +A single git repository may contain multiple branches. Each branch +is a bookmark referencing a particular point in the project history. +The gitlink:git-branch[1] command shows you the list of branches: + +------------------------------------------------ +$ git branch +* master +------------------------------------------------ + +A freshly cloned repository contains a single branch, named "master", +and the working directory contains the version of the project +referred to by the master branch. + +Most projects also use tags. Tags, like branches, are references +into the project's history, and can be listed using the +gitlink:git-tag[1] command: + +------------------------------------------------ +$ git tag -l +v2.6.11 +v2.6.11-tree +v2.6.12 +v2.6.12-rc2 +v2.6.12-rc3 +v2.6.12-rc4 +v2.6.12-rc5 +v2.6.12-rc6 +v2.6.13 +... +------------------------------------------------ + +Create a new branch pointing to one of these versions and check it +out using gitlink:git-checkout[1]: + +------------------------------------------------ +$ git checkout -b new v2.6.13 +------------------------------------------------ + +The working directory then reflects the contents that the project had +when it was tagged v2.6.13, and gitlink:git-branch[1] shows two +branches, with an asterisk marking the currently checked-out branch: + +------------------------------------------------ +$ git branch + master +* new +------------------------------------------------ + +If you decide that you'd rather see version 2.6.17, you can modify +the current branch to point at v2.6.17 instead, with + +------------------------------------------------ +$ git reset --hard v2.6.17 +------------------------------------------------ + +Note that if the current branch was your only reference to a +particular point in history, then resetting that branch may leave you +with no way to find the history it used to point to; so use this +command carefully. + +Understanding History: Commits +------------------------------ + +Every change in the history of a project is represented by a commit. +The gitlink:git-show[1] command shows the most recent commit on the +current branch: + +------------------------------------------------ +$ git show +commit 2b5f6dcce5bf94b9b119e9ed8d537098ec61c3d2 +Author: Jamal Hadi Salim +Date: Sat Dec 2 22:22:25 2006 -0800 + + [XFRM]: Fix aevent structuring to be more complete. + + aevents can not uniquely identify an SA. We break the ABI with this + patch, but consensus is that since it is not yet utilized by any + (known) application then it is fine (better do it now than later). + + Signed-off-by: Jamal Hadi Salim + Signed-off-by: David S. Miller + +diff --git a/Documentation/networking/xfrm_sync.txt b/Documentation/networking/xfrm_sync.txt +index 8be626f..d7aac9d 100644 +--- a/Documentation/networking/xfrm_sync.txt ++++ b/Documentation/networking/xfrm_sync.txt +@@ -47,10 +47,13 @@ aevent_id structure looks like: + + struct xfrm_aevent_id { + struct xfrm_usersa_id sa_id; ++ xfrm_address_t saddr; + __u32 flags; ++ __u32 reqid; + }; +... +------------------------------------------------ + +As you can see, a commit shows who made the latest change, what they +did, and why. + +Every commit has a 20-digit id, sometimes called the "SHA1 id", shown +on the first line of the "git show" output. You can usually refer to +a commit by a shorter name, such as a tag or a branch name, but this +longer id can also be useful. In particular, it is a globally unique +name for this commit: so if you tell somebody else the SHA1 id (for +example in email), then you are guaranteed they will see the same +commit in their repository that you do in yours. + +Understanding history: commits, parents, and reachability +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Every commit (except the very first commit in a project) also has a +parent commit which shows what happened before this commit. +Following the chain of parents will eventually take you back to the +beginning of the project. + +However, the commits do not form a simple list; git allows lines of +development to diverge and then reconverge, and the point where two +lines of development reconverge is called a "merge". The commit +representing a merge can therefore have more than one parent, with +each parent representing the most recent commit on one of the lines +of development leading to that point. + +The best way to see how this works is using the gitlink:gitk[1] +command; running gitk now on a git repository and looking for merge +commits will help understand how the git organizes history. + +In the following, we say that commit X is "reachable" from commit Y +if commit X is an ancestor of commit Y. Equivalently, you could say +that Y is a descendent of X, or that there is a chain of parents +leading from commit Y to commit X. + +Undestanding history: History diagrams +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +We will sometimes represent git history using diagrams like the one +below. Commits are shown as "o", and the links between them with +lines drawn with - / and \. Time goes left to right: + + o--o--o <-- Branch A + / + o--o--o <-- master + \ + o--o--o <-- Branch B + +If we need to talk about a particular commit, the character "o" may +be replaced with another letter or number. + +Understanding history: What is a branch? +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Though we've been using the word "branch" to mean a kind of reference +to a particular commit, the word branch is also commonly used to +refer to the line of commits leading up to that point. In the +example above, git may think of the branch named "A" as just a +pointer to one particular commit, but we may refer informally to the +line of three commits leading up to that point as all being part of +"branch A". + +If we need to make it clear that we're just talking about the most +recent commit on the branch, we may refer to that commit as the +"head" of the branch. + +Manipulating branches +--------------------- + +Creating, deleting, and modifying branches is quick and easy; here's +a summary of the commands: + +git branch:: + list all branches +git branch :: + create a new branch named , referencing the same + point in history as the current branch +git branch :: + create a new branch named , referencing + , which may be specified any way you like, + including using a branch name or a tag name +git branch -d :: + delete the branch ; if the branch you are deleting + points to a commit which is not reachable from this branch, + this command will fail with a warning. +git branch -D :: + even if the branch points to a commit not reachable + from the current branch, you may know that that commit + is still reachable from some other branch or tag. In that + case it is safe to use this command to force git to delete + the branch. +git checkout :: + make the current branch , updating the working + directory to reflect the version referenced by +git checkout -b :: + create a new branch referencing , and + check it out. + +It is also useful to know that the special symbol "HEAD" can always +be used to refer to the current branch. + +Examining branches from a remote repository +------------------------------------------- + +The "master" branch that was created at the time you cloned is a copy +of the HEAD in the repository that you cloned from. That repository +may also have had other branches, though, and your local repository +keeps branches which track each of those remote branches, which you +can view using the "-r" option to gitlink:git-branch[1]: + +------------------------------------------------ +$ git branch -r + origin/HEAD + origin/html + origin/maint + origin/man + origin/master + origin/next + origin/pu + origin/todo +------------------------------------------------ + +You cannot check out these remote-tracking branches, but you can +examine them on a branch of your own, just as you would a tag: + +------------------------------------------------ +$ git checkout -b my-todo-copy origin/todo +------------------------------------------------ + +Note that the name "origin" is just the name that git uses by default +to refer to the repository that you cloned from. + +[[how-git-stores-references]] +How git stores references +------------------------- + +Branches, remote-tracking branches, and tags are all references to +commits. Git stores these references in the ".git" directory. Most +of them are stored in .git/refs/: + + - branches are stored in .git/refs/heads + - tags are stored in .git/refs/tags + - remote-tracking branches for "origin" are stored in + .git/refs/remotes/origin/ + +If you look at one of these files you will see that they usually +contain just the SHA1 id of a commit: + +------------------------------------------------ +$ ls .git/refs/heads/ +master +$ cat .git/refs/heads/master +c0f982dcf188d55db9d932a39d4ea7becaa55fed +------------------------------------------------ + +You can refer to a reference by its path relative to the .git +directory. However, we've seen above that git will also accept +shorter names; for example, "master" is an acceptable shortcut for +"refs/heads/master", and "origin/master" is a shortcut for +"refs/remotes/origin/master". + +As another useful shortcut, you can also refer to the "HEAD" of +"origin" (or any other remote), using just the name of the remote. + +For the complete list of paths which git checks for references, and +how it decides which to choose when there are multiple references +with the same name, see the "SPECIFYING REVISIONS" section of +gitlink:git-rev-parse[1]. + +[[Updating-a-repository-with-git-fetch]] +Updating a repository with git fetch +------------------------------------ + +Eventually the developer cloned from will do additional work in her +repository, creating new commits and advancing the branches to point +at the new commits. + +The command "git fetch", with no arguments, will update all of the +remote-tracking branches to the latest version found in her +repository. It will not touch any of your own branches--not even the +"master" branch that was created for you on clone. + +Fetching individual branches +---------------------------- + +You can also choose to update just one branch at a time: + +------------------------------------------------- +$ git fetch origin todo:refs/remotes/origin/todo +------------------------------------------------- + +The first argument, "origin", just tells git to fetch from the +repository you originally cloned from. The second argument tells git +to fetch the branch named "todo" from the remote repository, and to +store it locally under the name refs/remotes/origin/todo; as we saw +above, remote-tracking branches are stored under +refs/remotes//. + +You can also fetch branches from other repositories; so + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:refs/remotes/example/master +------------------------------------------------- + +will create a new reference named "refs/remotes/example/master" and +store in it the branch named "master" from the repository at the +given URL. If you already have a branch named +"refs/remotes/example/master", it will attempt to "fast-forward" to +the commit given by example.com's master branch. So next we explain +what a fast-forward is: + +[[fast-forwards]] +Understanding git history: fast-forwards +---------------------------------------- + +In the previous example, when updating an existing branch, "git +fetch" checks to make sure that the most recent commit on the remote +branch is a descendant of the most recent commit on your copy of the +branch before updating your copy of the branch to point at the new +commit. Git calls this process a "fast forward". + +A fast forward looks something like this: + + o--o--o--o <-- old head of the branch + \ + o--o--o <-- new head of the branch + + +In some cases it is possible that the new head will *not* actually be +a descendant of the old head. For example, the developer may have +realized she made a serious mistake, and decided to backtrack, +resulting in a situation like: + + o--o--o--o--a--b <-- old head of the branch + \ + o--o--o <-- new head of the branch + + + +In this case, "git fetch" will fail, and print out a warning. + +In that case, you can still force git to update to the new head, as +described in the following section. However, note that in the +situation above this may mean losing the commits labeled "a" and "b", +unless you've already created a reference of your own pointing to +them. + +Forcing git fetch to do non-fast-forward updates +------------------------------------------------ + +If git fetch fails because the new head of a branch is not a +descendant of the old head, you may force the update with: + +------------------------------------------------- +$ git fetch git://example.com/proj.git +master:refs/remotes/example/master +------------------------------------------------- + +Note the addition of the "+" sign. Be aware that commits which the +old version of example/master pointed at may be lost, as we saw in +the previous section. + +Configuring remote branches +--------------------------- + +We saw above that "origin" is just a shortcut to refer to the +repository which you originally cloned from. This information is +stored in git configuration variables, which you can see using +gitlink:git-repo-config[1]: + +------------------------------------------------- +$ git-repo-config -l +core.repositoryformatversion=0 +core.filemode=true +core.logallrefupdates=true +remote.origin.url=git://git.kernel.org/pub/scm/git/git.git +remote.origin.fetch=+refs/heads/*:refs/remotes/origin/* +branch.master.remote=origin +branch.master.merge=refs/heads/master +------------------------------------------------- + +If there are other repositories that you also use frequently, you can +create similar configuration options to save typing; for example, +after + +------------------------------------------------- +$ git repo-config remote.example.url=git://example.com/proj.git +------------------------------------------------- + +then the following two commands will do the same thing: + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:refs/remotes/example/master +$ git fetch example master:refs/remotes/example/master +------------------------------------------------- + +Even better, if you add one more option: + +------------------------------------------------- +$ git repo-config remote.example.fetch=master:refs/remotes/example/master +------------------------------------------------- + +then the following commands will all do the same thing: + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:ref/remotes/example/master +$ git fetch example master:ref/remotes/example/master +$ git fetch example example/master +$ git fetch example +------------------------------------------------- + +You can also add a "+" to force the update each time: + +------------------------------------------------- +$ git repo-config +master:ref/remotes/example/master +------------------------------------------------- + +Don't do this unless you're sure you won't mind "git fetch" possibly +throwing away commits on mybranch. + +Also note that all of the above configuration can be performed by +directly editing the file .git/config instead of using +gitlink:git-repo-config[1]. + +See gitlink:git-repo-config[1] for more details on the configuration +options mentioned above. + +Exploring git history +===================== + +Git is best thought of as a tool for storing the history of a +collection of files. It does this by storing compressed snapshots of +the contents of a file heirarchy, together with "commits" which show +the relationships between these snapshots. + +Git provides extremely flexible and fast tools for exploring the +history of a project. + +We start with one specialized tool which is useful for finding the +commit that introduced a bug into a project. + +How to use bisect to find a regression +-------------------------------------- + +Suppose version 2.6.18 of your project worked, but the version at +"master" crashes. Sometimes the best way to find the cause of such a +regression is to perform a brute-force search through the project's +history to find the particular commit that caused the problem. The +gitlink:git-bisect[1] command can help you do this: + +------------------------------------------------- +$ git bisect start +$ git bisect good v2.6.18 +$ git bisect bad master +Bisecting: 3537 revisions left to test after this +[65934a9a028b88e83e2b0f8b36618fe503349f8e] BLOCK: Make USB storage depend on SCSI rather than selecting it [try #6] +------------------------------------------------- + +If you run "git branch" at this point, you'll see that git has +temporarily moved you to a new branch named "bisect". This branch +points to a commit (with commit id 65934...) that is reachable from +v2.6.19 but not from v2.6.18. Compile and test it, and see whether +it crashes. Assume it does crash. Then: + +------------------------------------------------- +$ git bisect bad +Bisecting: 1769 revisions left to test after this +[7eff82c8b1511017ae605f0c99ac275a7e21b867] i2c-core: Drop useless bitmaskings +------------------------------------------------- + +checks out an older version. Continue like this, telling git at each +stage whether the version it gives you is good or bad, and notice +that the number of revisions left to test is cut approximately in +half each time. + +After about 13 tests (in this case), it will output the commit id of +the guilty commit. You can then examine the commit with +gitlink:git-show[1], find out who wrote it, and mail them your bug +report with the commit id. Finally, run + +------------------------------------------------- +$ git bisect reset +------------------------------------------------- + +to return you to the branch you were on before and delete the +temporary "bisect" branch. + +Note that the version which git-bisect checks out for you at each +point is just a suggestion, and you're free to try a different +version if you think it would be a good idea. For example, +occasionally you may land on a commit that broke something unrelated; +run + +------------------------------------------------- +$ git bisect-visualize +------------------------------------------------- + +which will run gitk and label the commit it chose with a marker that +says "bisect". Chose a safe-looking commit nearby, note its commit +id, and check it out with: + +------------------------------------------------- +$ git reset --hard fb47ddb2db... +------------------------------------------------- + +then test, run "bisect good" or "bisect bad" as appropriate, and +continue. + +Naming commits +-------------- + +We have seen several ways of naming commits already: + + - 20-digit SHA1 id + - branch name: refers to the commit at the head of the given + branch + - tag name: refers to the commit pointed to by the given tag + (we've seen branches and tags are special cases of + <>). + - HEAD: refers to the head of the current branch + +There are many more; see the "SPECIFYING REVISION" section of the +gitlink:git-rev-list[1] man page for the complete list of ways to +name revisions. Some examples: + +------------------------------------------------- +$ git show fb47ddb2 # the first few characters of the SHA1 id + # are usually enough to specify it uniquely +$ git show HEAD^ # the parent of the HEAD commit +$ git show HEAD^^ # the grandparent +$ git show HEAD~4 # the great-great-grandparent +------------------------------------------------- + +Recall that merge commits may have more than one parent; by default, +^ and ~ follow the first parent listed in the commit, but you can +also choose: + +------------------------------------------------- +$ git show HEAD^1 # show the first parent of HEAD +$ git show HEAD^2 # show the second parent of HEAD +------------------------------------------------- + +In addition to HEAD, there are several other special names for +commits: + +Merges (to be discussed later), as well as operations such as +git-reset, which change the currently checked-out commit, generally +set ORIG_HEAD to the value HEAD had before the current operation. + +The git-fetch operation always stores the head of the last fetched +branch in FETCH_HEAD. For example, if you run git fetch without +specifying a local branch as the target of the operation + +------------------------------------------------- +$ git fetch git://example.com/proj.git theirbranch +------------------------------------------------- + +the fetched commits will still be available from FETCH_HEAD. + +When we discuss merges we'll also see the special name MERGE_HEAD, +which refers to the other branch that we're merging in to the current +branch. + +Creating tags +------------- + +We can also create a tag to refer to a particular commit; after +running + +------------------------------------------------- +$ git-tag stable-1 1b2e1d63ff +------------------------------------------------- + +You can use stable-1 to refer to the commit 1b2e1d63ff. + +This creates a "lightweight" tag. If the tag is a tag you wish to +share with others, and possibly sign cryptographically, then you +should create a tag object instead; see the gitlink:git-tag[1] man +page for details. + +Browsing revisions +------------------ + +The gitlink:git-log[1] command can show lists of commits. On its +own, it shows all commits reachable from the parent commit; but you +can also make more specific requests: + +------------------------------------------------- +$ git log v2.5.. # commits since (not reachable from) v2.5 +$ git log test..master # commits reachable from master but not test +$ git log master..test # ...reachable from test but not master +$ git log master...test # ...reachable from either test or master, + # but not both +$ git log --since="2 weeks ago" # commits from the last 2 weeks +$ git log Makefile # commits which modify Makefile +$ git log fs/ # ... which modify any file under fs/ +$ git log -S'foo()' # commits which add or remove any file data + # matching the string 'foo()' +------------------------------------------------- + +And of course you can combine all of these; the following finds +commits since v2.5 which touch the Makefile or any file under fs: + +------------------------------------------------- +$ git log v2.5.. Makefile fs/ +------------------------------------------------- + +You can also ask git log to show patches: + +------------------------------------------------- +$ git log -p +------------------------------------------------- + +See the "--pretty" option in the gitlink:git-log[1] man page for more +display options. + +Note that git log starts with the most recent commit and works +backwards through the parents; however, since git history can contain +multiple independant lines of development, the particular order that +commits are listed in may be somewhat arbitrary. + +Generating diffs +---------------- + +You can generate diffs between any two versions using +gitlink:git-diff[1]: + +------------------------------------------------- +$ git diff master..test +------------------------------------------------- + +Sometimes what you want instead is a set of patches: + +------------------------------------------------- +$ git format-patch master..test +------------------------------------------------- + +will generate a file with a patch for each commit reachable from test +but not from master. Note that if master also has commits which are +not reachable from test, then the combined result of these patches +will not be the same as the diff produced by the git-diff example. + +Viewing old file versions +------------------------- + +You can always view an old version of a file by just checking out the +correct revision first. But sometimes it is more convenient to be +able to view an old version of a single file without checking +anything out; this command does that: + +------------------------------------------------- +$ git show v2.5:fs/locks.c +------------------------------------------------- + +Before the colon may be anything that names a commit, and after it +may be any path to a file tracked by git. + +Developing with git +=================== + +Telling git your name +--------------------- + +Before creating any commits, you should introduce yourself to git. The +easiest way to do so is: + +------------------------------------------------ +$ cat >~/.gitconfig <<\EOF +[user] + name = Your Name Comes Here + email = you@yourdomain.example.com +EOF +------------------------------------------------ + + +Creating a new repository +------------------------- + +Creating a new repository from scratch is very easy: + +------------------------------------------------- +$ mkdir project +$ cd project +$ git init-db +------------------------------------------------- + +If you have some initial content (say, a tarball): + +------------------------------------------------- +$ tar -xzvf project.tar.gz +$ cd project +$ git init-db +$ git add . # include everything below ./ in the first commit: +$ git commit +------------------------------------------------- + +[[how-to-make-a-commit]] +how to make a commit +-------------------- + +Creating a new commit takes three steps: + + 1. Making some changes to the working directory using your + favorite editor. + 2. Telling git about your changes. + 3. Creating the commit using the content you told git about + in step 2. + +In practice, you can interleave and repeat steps 1 and 2 as many +times as you want: in order to keep track of what you want committed +at step 3, git maintains a snapshot of the tree's contents in a +special staging area called "the index." + +By default, the content of the index is identical to that of the +HEAD. The command "git diff --cached" shows the difference between +HEAD and the index, so you should no output from that command. + +Modifying the index is easy: + +To update the index with the new contents of a modified file, use + +------------------------------------------------- +$ git add path/to/file +------------------------------------------------- + +To add the contents of a new file to the index, use + +------------------------------------------------- +$ git add path/to/file +------------------------------------------------- + +To remove a file from the index that you've removed from the working +tree, + +------------------------------------------------- +$ git rm path/to/file +------------------------------------------------- + +After each step you can verify that + +------------------------------------------------- +$ git diff --cached +------------------------------------------------- + +always shows the difference between the HEAD and the index file--this +is what you'd commit if you created the commit now--and that + +------------------------------------------------- +$ git diff +------------------------------------------------- + +shows the difference between the working tree and the index file. + +Note that "git add" always adds just the current contents of a file +to the index; further changes to the same file will be ignored unless +you run git-add on the file again. + +When you're ready, just run + +------------------------------------------------- +$ git commit +------------------------------------------------- + +and git will prompt you for a commit message and then create the new +commmit. Check to make sure it looks like what you expected with + +------------------------------------------------- +$ git show +------------------------------------------------- + +As a special shortcut, + +------------------------------------------------- +$ git commit -a +------------------------------------------------- + +will update the index with any files that you've modified or removed +and create a commit, all in one step. + +A number of commands are useful for keeping track of what you're +about to commit: + +------------------------------------------------- +$ git diff --cached # difference between HEAD and the index; what + # would be commited if you ran "commit" now. +$ git diff # difference between the index file and your + # working directory; changes that would not + # be included if you ran "commit" now. +$ git status # a brief per-file summary of the above. +------------------------------------------------- + +creating good commit messages +----------------------------- + +Though not required, it's a good idea to begin the commit message +with a single short (less than 50 character) line summarizing the +change, followed by a blank line and then a more thorough +description. Tools that turn commits into email, for example, use +the first line on the Subject line and the rest of the commit in the +body. + +how to merge +------------ + +You can rejoin two diverging branches of development using +gitlink:git-merge[1]: + +------------------------------------------------- +$ git merge branchname +------------------------------------------------- + +merges the development in the branch "branchname" into the current +branch. If there are conflicts--for example, if the same file is +modified in two different ways in the remote branch and the local +branch--then you are warned; the output may look something like this: + +------------------------------------------------- +$ git pull . next +Trying really trivial in-index merge... +fatal: Merge requires file-level merging +Nope. +Merging HEAD with 77976da35a11db4580b80ae27e8d65caf5208086 +Merging: +15e2162 world +77976da goodbye +found 1 common ancestor(s): +d122ed4 initial +Auto-merging file.txt +CONFLICT (content): Merge conflict in file.txt +Automatic merge failed; fix conflicts and then commit the result. +------------------------------------------------- + +Conflict markers are left in the problematic files, and after +you resolve the conflicts manually, you can update the index +with the contents and run git commit, as you normally would when +creating a new file. + +If you examine the resulting commit using gitk, you will see that it +has two parents, one pointing to the top of the current branch, and +one to the top of the other branch. + +In more detail: + +[[resolving-a-merge]] +Resolving a merge +----------------- + +When a merge isn't resolved automatically, git leaves the index and +the working tree in a special state that gives you all the +information you need to help resolve the merge. + +Files with conflicts are marked specially in the index, so until you +resolve the problem and update the index, git commit will fail: + +------------------------------------------------- +$ git commit +file.txt: needs merge +------------------------------------------------- + +Also, git status will list those files as "unmerged". + +All of the changes that git was able to merge automatically are +already added to the index file, so gitlink:git-diff[1] shows only +the conflicts. Also, it uses a somewhat unusual syntax: + +------------------------------------------------- +$ git diff +diff --cc file.txt +index 802992c,2b60207..0000000 +--- a/file.txt ++++ b/file.txt +@@@ -1,1 -1,1 +1,5 @@@ +++<<<<<<< HEAD:file.txt + +Hello world +++======= ++ Goodbye +++>>>>>>> 77976da35a11db4580b80ae27e8d65caf5208086:file.txt +------------------------------------------------- + +Recall that the commit which will be commited after we resolve this +conflict will have two parents instead of the usual one: one parent +will be HEAD, the tip of the current branch; the other will be the +tip of the other branch, which is stored temporarily in MERGE_HEAD. + +The diff above shows the differences between the working-tree version +of file.txt and two previous version: one version from HEAD, and one +from MERGE_HEAD. So instead of preceding each line by a single "+" +or "-", it now uses two columns: the first column is used for +differences between the first parent and the working directory copy, +and the second for differences between the second parent and the +working directory copy. Thus after resolving the conflict in the +obvious way, the diff will look like: + +------------------------------------------------- +$ git diff +diff --cc file.txt +index 802992c,2b60207..0000000 +--- a/file.txt ++++ b/file.txt +@@@ -1,1 -1,1 +1,1 @@@ +- Hello world + -Goodbye +++Goodbye world +------------------------------------------------- + +This shows that our resolved version deleted "Hello world" from the +first parent, deleted "Goodbye" from the second parent, and added +"Goodbye world", which was previously absent from both. + +The gitlink:git-log[1] command also provides special help for merges: + +------------------------------------------------- +$ git log --merge +------------------------------------------------- + +This will list all commits which exist only on HEAD or on MERGE_HEAD, +and which touch an unmerged file. + +We can now add the resolved version to the index and commit: + +------------------------------------------------- +$ git add file.txt +$ git commit +------------------------------------------------- + +Note that the commit message will already be filled in for you with +some information about the merge. Normally you can just use this +default message unchanged, but you may add additional commentary of +your own if desired. + +[[undoing-a-merge]] +undoing a merge +--------------- + +If you get stuck and decide to just give up and throw the whole mess +away, you can always return to the pre-merge state with + +------------------------------------------------- +$ git reset --hard HEAD +------------------------------------------------- + +Or, if you've already commited the merge that you want to throw away, + +------------------------------------------------- +$ git reset --hard HEAD^ +------------------------------------------------- + +However, this last command can be dangerous in some cases--never +throw away a commit you have already committed if that commit may +itself have been merged into another branch, as doing so may confuse +further merges. + +Fast-forward merges +------------------- + +There is one special case not mentioned above, which is treated +differently. Normally, a merge results in a merge commit, with two +parents, one pointing at each of the two lines of development that +were merged. + +However, if one of the two lines of development is completely +contained within the other--so every commit present in the one is +already contained in the other--then git just performs a +<>; the head of the current branch is +moved forward to point at the head of the merged-in branch, without +any new commits being created. + +Ensuring good performance +------------------------- + +On large repositories, git depends on compression to keep the history +information from taking up to much space on disk or in memory. + +This compression is not performed automatically. Therefore you +should occasionally run + +------------------------------------------------- +$ git gc +------------------------------------------------- + +to recompress the archive and to prune any commits which are no +longer referred to anywhere. This can be very time-consuming, and +you should not modify the repository while it is working, so you +should run it while you are not working. + +Sharing development with others +------------------------------- + +[[getting-updates-with-git-pull]] +Getting updates with git pull +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +After you clone a repository and make a few changes of your own, you +may wish to check the original repository for updates and merge them +into your own work. + +We have already seen <> with gitlink:git-fetch[1], +and how to merge two branches. So you can merge in changes from the +original repository's master branch with: + +------------------------------------------------- +$ git fetch +$ git merge origin/master +------------------------------------------------- + +However, the gitlink:git-pull[1] command provides a way to do this in +one step: + +------------------------------------------------- +$ git pull origin master +------------------------------------------------- + +In fact, "origin" is normally the default repository to pull from, +and the default branch is normally the HEAD of the remote repository, +so often you can accomplish the above with just + +------------------------------------------------- +$ git pull +------------------------------------------------- + +See the descriptions of the branch..remote and +branch..merge options in gitlink:git-repo-config[1] to learn +how to control these defaults depending on the current branch. + +In addition to saving you keystrokes, "git pull" also helps you by +producing a default commit message documenting the branch and +repository that you pulled from. + +(But note that no such commit will be created in the case of a +<>; instead, your branch will just be +updated to point to the latest commit from the upstream branch). + +Submitting patches to a project +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If you just have a few changes, the simplest way to submit them may +just be to send them as patches in email: + +First, use gitlink:git-format-patches[1]; for example: + +------------------------------------------------- +$ git format-patches origin +------------------------------------------------- + +will produce a numbered series of files in the current directory, one +for each patch in the current branch but not in origin/HEAD. + +You can then import these into your mail client and send them by +hand. However, if you have a lot to send at once, you may prefer to +use the gitlink:git-send-email[1] script to automate the process. +Consult the mailing list for your project first to determine how they +prefer such patches be handled. + +Importing patches to a project +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Git also provides a tool called gitlink:git-am[1] (am stands for +"apply mailbox"), for importing such an emailed series of patches. +Just save all of the patch-containing messages, in order, into a +single mailbox file, say "patches.mbox", then run + +------------------------------------------------- +$ git am patches.mbox +------------------------------------------------- + +Git will apply each patch in order; if any conflicts are found, it +will stop, and you can fix the conflicts as described in +"<>". Once the index is updated +with the results of the conflict resolution, instead of creating a +new commit, just run + +------------------------------------------------- +$ git am --resolved +------------------------------------------------- + +and git will create the commit for you and continue applying the +remaining patches from the mailbox. + +The final result will be a series of commits, one for each patch in +the original mailbox, with authorship and commit log message each +taken from the message containing each patch. + +[[setting-up-a-public-repository]] +Setting up a public repository +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Another way to submit changes to a project is to simply tell the +maintainer of that project to pull from your repository, exactly as +you did in the section "<>". + +If you and maintainer both have accounts on the same machine, then +then you can just pull changes from each other's repositories +directly; note that all of the command (gitlink:git-clone[1], +git-fetch[1], git-pull[1], etc.) which accept a URL as an argument +will also accept a local file patch; so, for example, you can +use + +------------------------------------------------- +$ git clone /path/to/repository +$ git pull /path/to/other/repository +------------------------------------------------- + +If this sort of setup is inconvenient or impossible, another (more +common) option is to set up a public repository on a public server. +This also allows you to cleanly separate private work in progress +from publicly visible work. + +You will continue to do your day-to-day work in your personal +repository, but periodically "push" changes from your personal +repository into your public repository, allowing other developers to +pull from that repository. So the flow of changes, in a situation +where there is one other developer with a public repository, looks +like this: + + you push + your personal repo ------------------> your public repo + ^ | + | | + | you pull | they pull + | | + | | + | they push V + their public repo <------------------- their repo + +Now, assume your personal repository is in the directory ~/proj. We +first create a new clone of the repository: + +------------------------------------------------- +$ git clone --bare proj-clone.git +------------------------------------------------- + +The resulting directory proj-clone.git will contains a "bare" git +repository--it is just the contents of the ".git" directory, without +a checked-out copy of a working directory. + +Next, copy proj-clone.git to the server where you plan to host the +public repository. You can use scp, rsync, or whatever is most +convenient. + +If somebody else maintains the public server, they may already have +set up a git service for you, and you may skip to the section +"<>", below. + +Otherwise, the following sections explain how to export your newly +created public repository: + +[[exporting-via-http]] +Exporting a git repository via http +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The git protocol gives better performance and reliability, but on a +host with a web server set up, http exports may be simpler to set up. + +All you need to do is place the newly created bare git repository in +a directory that is exported by the web server, and make some +adjustments to give web clients some extra information they need: + +------------------------------------------------- +$ mv proj.git /home/you/public_html/proj.git +$ cd proj.git +$ git update-server-info +$ chmod a+x hooks/post-update +------------------------------------------------- + +(For an explanation of the last two lines, see +gitlink:git-update-server-info[1], and the documentation +link:hooks.txt[Hooks used by git].) + +Advertise the url of proj.git. Anybody else should then be able to +clone or pull from that url, for example with a commandline like: + +------------------------------------------------- +$ git clone http://yourserver.com/~you/proj.git +------------------------------------------------- + +(See also +link:howto/setup-git-server-over-http.txt[setup-git-server-over-http] +for a slightly more sophisticated setup using WebDAV which also +allows pushing over http.) + +[[exporting-via-git]] +Exporting a git repository via the git protocol +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This is the preferred method. + +For now, we refer you to the gitlink:git-daemon[1] man page for +instructions. (See especially the examples section.) + +[[pushing-changes-to-a-public-repository]] +Pushing changes to a public repository +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Note that the two techniques outline above (exporting via +<> or <>) allow other +maintainers to fetch your latest changes, but they do not allow write +access, which you will need to update the public repository with the +latest changes created in your private repository. + +The simplest way to do this is using gitlink:git-push[1] and ssh; to +update the remote branch named "master" with the latest state of your +branch named "master", run + +------------------------------------------------- +$ git push ssh://yourserver.com/~you/proj.git master:master +------------------------------------------------- + +or just + +------------------------------------------------- +$ git push ssh://yourserver.com/~you/proj.git master +------------------------------------------------- + +As with git-fetch, git-push will complain if this does not result in +a <>. Normally this is a sign of +something wrong. However, if you are sure you know what you're +doing, you may force git-push to perform the update anyway by +proceeding the branch name by a plus sign: + +------------------------------------------------- +$ git push ssh://yourserver.com/~you/proj.git +master +------------------------------------------------- + +As with git-fetch, you may also set up configuration options to +save typing; so, for example, after + +------------------------------------------------- +$ cat >.git/config <.url, branch..remote, +and remote..push options in gitlink:git-repo-config[1] for +details. + +Setting up a shared repository +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Another way to collaborate is by using a model similar to that +commonly used in CVS, where several developers with special rights +all push to and pull from a single shared repository. See +link:cvs-migration.txt[git for CVS users] for instructions on how to +set this up. + +Fixing mistakes +--------------- + +If you've messed up the working tree, but haven't yet committed your +mistake, you can return the entire working tree to the last committed +state with + +------------------------------------------------- +$ git reset --hard HEAD +------------------------------------------------- + +If you make a commit that you later wish you hadn't, there are two +fundamentally different ways to fix the problem: + + 1. You can create a new commit that undoes whatever was done + by the previous commit. This is the correct thing if your + mistake has already been made public. + + 2. You can go back and modify the old commit. You should + never do this if you have already made the history public; + git does not normally expect the "history" of a project to + change, and cannot correctly perform repeated merges from + a branch that has had its history changed. + +Fixing a mistake with a new commit +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Creating a new commit that reverts an earlier change is very easy; +just pass the gitlink:git-revert[1] command a reference to the bad +commit; for example, to revert the most recent commit: + +------------------------------------------------- +$ git revert HEAD +------------------------------------------------- + +This will create a new commit which undoes the change in HEAD. You +will be given a chance to edit the commit message for the new commit. + +You can also revert an earlier change, for example, the next-to-last: + +------------------------------------------------- +$ git revert HEAD^ +------------------------------------------------- + +In this case git will attempt to undo the old change while leaving +intact any changes made since then. If more recent changes overlap +with the changes to be reverted, then you will be asked to fix +conflicts manually, just as in the case of <>. + +Fixing a mistake by editing history +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If the problematic commit is the most recent commit, and you have not +yet made that commit public, then you may just +<>. + +Alternatively, you +can edit the working directory and update the index to fix your +mistake, just as if you were going to <>, then run + +------------------------------------------------- +$ git commit --amend +------------------------------------------------- + +which will replace the old commit by a new commit incorporating your +changes, giving you a chance to edit the old commit message first. + +Again, you should never do this to a commit that may already have +been merged into another branch; use gitlink:git-revert[1] instead in +that case. + +It is also possible to edit commits further back in the history, but +this is an advanced topic to be left for +<>. + +Checking out an old version of a file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +In the process of undoing a previous bad change, you may find it +useful to check out an older version of a particular file using +gitlink:git-checkout[1]. We've used git checkout before to switch +branches, but it has quite different behavior if it is given a path +name: the command + +------------------------------------------------- +$ git checkout HEAD^ path/to/file +------------------------------------------------- + +replaces path/to/file by the contents it had in the commit HEAD^, and +also updates the index to match. It does not change branches. + +If you just want to look at an old version of the file, without +modifying the working directory, you can do that with +gitlink:git-show[1]: + +------------------------------------------------- +$ git show HEAD^ path/to/file +------------------------------------------------- + +which will display the given version of the file. + +Working with other version control systems +========================================== + +TODO: CVS, Subversion, ? + +[[cleaning-up-history]] +Cleaning up history: rebasing, cherry-picking, and patch series +=============================================================== + +TODO: rebase, cherry-pick, pointers to other tools (like stgit) + +Git internals +============= + +Architectural overview +---------------------- + +TODO: Sources, README, core-tutorial, tutorial-2.txt, technical/ + +Glossary of git terms +===================== + +include::glossary.txt[] + +Todo list for this manual +========================= + +Scan Documentation/ for other stuff left out; in particular: + howto's + README + some of technical/? + hooks + etc. + +Scan email archives for other stuff left out + +Scan man pages to see if any assume more background than this manual +provides. + +Mention of gitweb. + +Update git fetch discussion to use "git remote" setup. That will +make things simpler. Maybe wait till git remote is done. + +Can also simplify beginning by suggesting disconnected head instead +of temporary branch creation. + +Explain how to refer to file stages in the "how to resolve a merge" +section: diff -1, -2, -3; :1:/path notation. + +Include cross-references to the glossary, where appropriate. + -- cgit v0.10.2-6-g49f6 From 6bd9b6822f7647cb3275cf151ca92c6d6e9423aa Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 7 Jan 2007 22:58:14 -0500 Subject: Documentation: expand preface and todo's Add a brief description of the organization to the preface, expand the final notes/todo's section, in hopes maybe some others will want to contribute. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 30ad103..1883147 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -4,6 +4,15 @@ _________________ This manual is designed to be readable by someone with basic unix commandline skills, but no previous knowledge of git. +Chapters 1 and 2 explain how to fetch and study a project using git--the +tools you'd need to build and test a particular version of a software +project, to search for regressions, and so on. + +Chapter 3 explains how to do development with git and share your progress +with others. + +Further chapters cover more specialized topics. + Comprehensive reference documentation is available through the man pages. For a command such as "git clone", just use @@ -1430,8 +1439,24 @@ Glossary of git terms include::glossary.txt[] -Todo list for this manual -========================= +Notes and todo list for this manual +=================================== + +This is a work in progress. + +The basic requirements: + - It must be readable in order, from beginning to end, by someone + intelligent with a basic grasp of the unix commandline, but + without any special knowledge of git. If necessary, any other + prerequisites should be specifically mentioned as they arise. + - Whenever possible, section headings should clearly describe the + task they explain how to do, in language that requires no more + knowledge than necessary: for example, "importing patches into a + project" rather than "the git-am command" + +Think about how to create a clear chapter dependency graph that will allow +people to get to important topics without necessarily reading everything +in between. Scan Documentation/ for other stuff left out; in particular: howto's @@ -1454,7 +1479,7 @@ Can also simplify beginning by suggesting disconnected head instead of temporary branch creation. Explain how to refer to file stages in the "how to resolve a merge" -section: diff -1, -2, -3; :1:/path notation. +section: diff -1, -2, -3, --ours, --theirs :1:/path notation. Include cross-references to the glossary, where appropriate. -- cgit v0.10.2-6-g49f6 From 4c63ff452ff04cd13819bf05f30e0df55b50510f Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 7 Jan 2007 23:57:41 -0500 Subject: Documentation: git-rebase discussion, miscellaneous user-manual updates Add discussion of git-rebase, patch series, history rewriting. Mention "pull ." as a synonym for "merge". Remind myself of another case I want to cover in the other-vcs's chapter. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 1883147..b699c9b 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1090,6 +1090,17 @@ repository that you pulled from. <>; instead, your branch will just be updated to point to the latest commit from the upstream branch). +The git-pull command can also be given "." as the "remote" repository, in +which case it just merges in a branch from the current repository; so +the commands + +------------------------------------------------- +$ git pull . branch +$ git merge branch +------------------------------------------------- + +are roughly equivalent. The former is actually very commonly used. + Submitting patches to a project ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1418,13 +1429,155 @@ which will display the given version of the file. Working with other version control systems ========================================== -TODO: CVS, Subversion, ? +TODO: CVS, Subversion, series-of-release-tarballs, ? [[cleaning-up-history]] -Cleaning up history: rebasing, cherry-picking, and patch series -=============================================================== +Rewriting history and maintaining patch series +============================================== + +Normally commits are only added to a project, never taken away or +replaced. Git is designed with this assumption, and violating it will +cause git's merge machinery (for example) to do the wrong thing. + +However, there is a situation in which it can be useful to violate this +assumption. + +Creating the perfect patch series +--------------------------------- + +Suppose you are a contributor to a large project, and you want to add a +complicated feature, and to present it to the other developers in a way +that makes it easy for them to read your changes, verify that they are +correct, and understand why you made each change. + +If you present all of your changes as a single patch (or commit), they may +find it is too much to digest all at once. + +If you present them with the entire history of your work, complete with +mistakes, corrections, and dead ends, they may be overwhelmed. + +So the ideal is usually to produce a series of patches such that: + + 1. Each patch can be applied in order. + + 2. Each patch includes a single logical change, together with a + message explaining the change. + + 3. No patch introduces a regression: after applying any initial + part of the series, the resulting project still compiles and + works, and has no bugs that it didn't have before. + + 4. The complete series produces the same end result as your own + (probably much messier!) development process did. + +We will introduce some tools that can help you do this, explain how to use +them, and then explain some of the problems that can arise because you are +rewriting history. + +Keeping a patch series up to date using git-rebase +-------------------------------------------------- + +Suppose you have a series of commits in a branch "mywork", which +originally branched off from "origin". + +Suppose you create a branch "mywork" on a remote-tracking branch "origin", +and created some commits on top of it: + +------------------------------------------------- +$ git checkout -b mywork origin +$ vi file.txt +$ git commit +$ vi otherfile.txt +$ git commit +... +------------------------------------------------- + +You have performed no merges into mywork, so it is just a simple linear +sequence of patches on top of "origin": + + + o--o--o <-- origin + \ + o--o--o <-- mywork + +Some more interesting work has been done in the upstream project, and +"origin" has advanced: + + o--o--O--o--o--o <-- origin + \ + a--b--c <-- mywork + +At this point, you could use "pull" to merge your changes back in; +the result would create a new merge commit, like this: + + + o--o--O--o--o--o <-- origin + \ \ + a--b--c--m <-- mywork + +However, if you prefer to keep the history in mywork a simple series of +commits without any merges, you may instead choose to use +gitlink:git-rebase[1]: + +------------------------------------------------- +$ git checkout mywork +$ git rebase origin +------------------------------------------------- + +This will remove each of your commits from mywork, temporarily saving them +as patches (in a directory named ".dotest"), update mywork to point at the +latest version of origin, then apply each of the saved patches to the new +mywork. The result will look like: + + + o--o--O--o--o--o <-- origin + \ + a'--b'--c' <-- mywork + +In the process, it may discover conflicts. In that case it will stop and +allow you to fix the conflicts as described in +"<>". Once the index is updated with +the results of the conflict resolution, instead of creating a new commit, +just run + +------------------------------------------------- +$ git rebase --continue +------------------------------------------------- + +and git will continue applying the rest of the patches. + +At any point you may use the --abort option to abort this process and +return mywork to the state it had before you started the rebase: + +------------------------------------------------- +$ git rebase --abort +------------------------------------------------- + +Reordering or selecting from a patch series +------------------------------------------- + +Given one existing commit, the gitlink:git-cherry-pick[1] command allows +you to apply the change introduced by that commit and create a new commit +that records it. + +This can be useful for modifying a patch series. + +TODO: elaborate + +Other tools +----------- + +There are numerous other tools, such as stgit, which exist for the purpose +of maintianing a patch series. These are out of the scope of this manual. + +Problems with rewriting history +------------------------------- + +The primary problem with rewriting the history of a branch has to do with +merging. + +TODO: elaborate -TODO: rebase, cherry-pick, pointers to other tools (like stgit) Git internals ============= -- cgit v0.10.2-6-g49f6 From e9c0390a9251714f4f4b54b4e3dddb2e65d18fa8 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 8 Jan 2007 21:59:42 -0500 Subject: Documentation: more user-manual todo's Add some more todo's for the user manual. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index b699c9b..a2fd5d2 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1632,7 +1632,22 @@ Can also simplify beginning by suggesting disconnected head instead of temporary branch creation. Explain how to refer to file stages in the "how to resolve a merge" -section: diff -1, -2, -3, --ours, --theirs :1:/path notation. +section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The +"git ls-files --unmerged --stage" thing is sorta useful too, actually. And +note gitk --merge. Also what's easiest way to see common merge base? + +Add more good examples. Entire sections of just cookbook examples might be a +good idea; maybe make an "advanced examples" section a standard end-of-chapter +section? Include cross-references to the glossary, where appropriate. +Update for detached-head. + +Update for git-remote. Even if the command isn't there yet, I think we should +probably just document the repository configuration necessary to set it up, as +the default way to keep a repository up-to-date. + +To document: + reflogs, git reflog expire + shallow clones?? See draft 1.5.0 release notes for some documentation. -- cgit v0.10.2-6-g49f6 From b684f830cc071c99ede9861c84e3b1e54549f6c7 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 8 Jan 2007 23:42:36 -0500 Subject: Documentation: reorder development section, todo's Update todo's. Split out "sharing development" section into a separate chapter, reorder. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index a2fd5d2..5433d62 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1024,6 +1024,109 @@ already contained in the other--then git just performs a moved forward to point at the head of the merged-in branch, without any new commits being created. +Fixing mistakes +--------------- + +If you've messed up the working tree, but haven't yet committed your +mistake, you can return the entire working tree to the last committed +state with + +------------------------------------------------- +$ git reset --hard HEAD +------------------------------------------------- + +If you make a commit that you later wish you hadn't, there are two +fundamentally different ways to fix the problem: + + 1. You can create a new commit that undoes whatever was done + by the previous commit. This is the correct thing if your + mistake has already been made public. + + 2. You can go back and modify the old commit. You should + never do this if you have already made the history public; + git does not normally expect the "history" of a project to + change, and cannot correctly perform repeated merges from + a branch that has had its history changed. + +Fixing a mistake with a new commit +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Creating a new commit that reverts an earlier change is very easy; +just pass the gitlink:git-revert[1] command a reference to the bad +commit; for example, to revert the most recent commit: + +------------------------------------------------- +$ git revert HEAD +------------------------------------------------- + +This will create a new commit which undoes the change in HEAD. You +will be given a chance to edit the commit message for the new commit. + +You can also revert an earlier change, for example, the next-to-last: + +------------------------------------------------- +$ git revert HEAD^ +------------------------------------------------- + +In this case git will attempt to undo the old change while leaving +intact any changes made since then. If more recent changes overlap +with the changes to be reverted, then you will be asked to fix +conflicts manually, just as in the case of <>. + +Fixing a mistake by editing history +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If the problematic commit is the most recent commit, and you have not +yet made that commit public, then you may just +<>. + +Alternatively, you +can edit the working directory and update the index to fix your +mistake, just as if you were going to <>, then run + +------------------------------------------------- +$ git commit --amend +------------------------------------------------- + +which will replace the old commit by a new commit incorporating your +changes, giving you a chance to edit the old commit message first. + +Again, you should never do this to a commit that may already have +been merged into another branch; use gitlink:git-revert[1] instead in +that case. + +It is also possible to edit commits further back in the history, but +this is an advanced topic to be left for +<>. + +Checking out an old version of a file +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +In the process of undoing a previous bad change, you may find it +useful to check out an older version of a particular file using +gitlink:git-checkout[1]. We've used git checkout before to switch +branches, but it has quite different behavior if it is given a path +name: the command + +------------------------------------------------- +$ git checkout HEAD^ path/to/file +------------------------------------------------- + +replaces path/to/file by the contents it had in the commit HEAD^, and +also updates the index to match. It does not change branches. + +If you just want to look at an old version of the file, without +modifying the working directory, you can do that with +gitlink:git-show[1]: + +------------------------------------------------- +$ git show HEAD^ path/to/file +------------------------------------------------- + +which will display the given version of the file. + Ensuring good performance ------------------------- @@ -1043,11 +1146,11 @@ you should not modify the repository while it is working, so you should run it while you are not working. Sharing development with others -------------------------------- +=============================== [[getting-updates-with-git-pull]] Getting updates with git pull -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +----------------------------- After you clone a repository and make a few changes of your own, you may wish to check the original repository for updates and merge them @@ -1102,7 +1205,7 @@ $ git merge branch are roughly equivalent. The former is actually very commonly used. Submitting patches to a project -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +------------------------------- If you just have a few changes, the simplest way to submit them may just be to send them as patches in email: @@ -1123,7 +1226,7 @@ Consult the mailing list for your project first to determine how they prefer such patches be handled. Importing patches to a project -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +------------------------------ Git also provides a tool called gitlink:git-am[1] (am stands for "apply mailbox"), for importing such an emailed series of patches. @@ -1153,7 +1256,7 @@ taken from the message containing each patch. [[setting-up-a-public-repository]] Setting up a public repository -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +------------------------------ Another way to submit changes to a project is to simply tell the maintainer of that project to pull from your repository, exactly as @@ -1219,7 +1322,7 @@ created public repository: [[exporting-via-http]] Exporting a git repository via http -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +----------------------------------- The git protocol gives better performance and reliability, but on a host with a web server set up, http exports may be simpler to set up. @@ -1253,7 +1356,7 @@ allows pushing over http.) [[exporting-via-git]] Exporting a git repository via the git protocol -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +----------------------------------------------- This is the preferred method. @@ -1262,7 +1365,7 @@ instructions. (See especially the examples section.) [[pushing-changes-to-a-public-repository]] Pushing changes to a public repository -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +-------------------------------------- Note that the two techniques outline above (exporting via <> or <>) allow other @@ -1315,7 +1418,7 @@ and remote..push options in gitlink:git-repo-config[1] for details. Setting up a shared repository -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +------------------------------ Another way to collaborate is by using a model similar to that commonly used in CVS, where several developers with special rights @@ -1323,108 +1426,16 @@ all push to and pull from a single shared repository. See link:cvs-migration.txt[git for CVS users] for instructions on how to set this up. -Fixing mistakes ---------------- - -If you've messed up the working tree, but haven't yet committed your -mistake, you can return the entire working tree to the last committed -state with - -------------------------------------------------- -$ git reset --hard HEAD -------------------------------------------------- - -If you make a commit that you later wish you hadn't, there are two -fundamentally different ways to fix the problem: - - 1. You can create a new commit that undoes whatever was done - by the previous commit. This is the correct thing if your - mistake has already been made public. - - 2. You can go back and modify the old commit. You should - never do this if you have already made the history public; - git does not normally expect the "history" of a project to - change, and cannot correctly perform repeated merges from - a branch that has had its history changed. - -Fixing a mistake with a new commit -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Creating a new commit that reverts an earlier change is very easy; -just pass the gitlink:git-revert[1] command a reference to the bad -commit; for example, to revert the most recent commit: - -------------------------------------------------- -$ git revert HEAD -------------------------------------------------- - -This will create a new commit which undoes the change in HEAD. You -will be given a chance to edit the commit message for the new commit. - -You can also revert an earlier change, for example, the next-to-last: - -------------------------------------------------- -$ git revert HEAD^ -------------------------------------------------- - -In this case git will attempt to undo the old change while leaving -intact any changes made since then. If more recent changes overlap -with the changes to be reverted, then you will be asked to fix -conflicts manually, just as in the case of <>. - -Fixing a mistake by editing history -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Allow web browsing of a repository +---------------------------------- -If the problematic commit is the most recent commit, and you have not -yet made that commit public, then you may just -<>. +TODO: Brief setup-instructions for gitweb -Alternatively, you -can edit the working directory and update the index to fix your -mistake, just as if you were going to <>, then run +Examples +-------- -------------------------------------------------- -$ git commit --amend -------------------------------------------------- +TODO: topic branches, typical roles as in everyday.txt, ? -which will replace the old commit by a new commit incorporating your -changes, giving you a chance to edit the old commit message first. - -Again, you should never do this to a commit that may already have -been merged into another branch; use gitlink:git-revert[1] instead in -that case. - -It is also possible to edit commits further back in the history, but -this is an advanced topic to be left for -<>. - -Checking out an old version of a file -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -In the process of undoing a previous bad change, you may find it -useful to check out an older version of a particular file using -gitlink:git-checkout[1]. We've used git checkout before to switch -branches, but it has quite different behavior if it is given a path -name: the command - -------------------------------------------------- -$ git checkout HEAD^ path/to/file -------------------------------------------------- - -replaces path/to/file by the contents it had in the commit HEAD^, and -also updates the index to match. It does not change branches. - -If you just want to look at an old version of the file, without -modifying the working directory, you can do that with -gitlink:git-show[1]: - -------------------------------------------------- -$ git show HEAD^ path/to/file -------------------------------------------------- - -which will display the given version of the file. Working with other version control systems ========================================== @@ -1623,10 +1634,8 @@ Scan email archives for other stuff left out Scan man pages to see if any assume more background than this manual provides. -Mention of gitweb. - -Update git fetch discussion to use "git remote" setup. That will -make things simpler. Maybe wait till git remote is done. +Update git fetch discussion to use "git remote", move most of branch +discussion till later. Can also simplify beginning by suggesting disconnected head instead of temporary branch creation. @@ -1636,18 +1645,12 @@ section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The "git ls-files --unmerged --stage" thing is sorta useful too, actually. And note gitk --merge. Also what's easiest way to see common merge base? -Add more good examples. Entire sections of just cookbook examples might be a -good idea; maybe make an "advanced examples" section a standard end-of-chapter -section? +Add more good examples. Entire sections of just cookbook examples might +be a good idea; maybe make an "advanced examples" section a standard +end-of-chapter section? Include cross-references to the glossary, where appropriate. -Update for detached-head. - -Update for git-remote. Even if the command isn't there yet, I think we should -probably just document the repository configuration necessary to set it up, as -the default way to keep a repository up-to-date. - To document: reflogs, git reflog expire shallow clones?? See draft 1.5.0 release notes for some documentation. -- cgit v0.10.2-6-g49f6 From d5cd5de495654ec2454e8c37829c5e1c9f49b66a Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 9 Jan 2007 00:18:09 -0500 Subject: Documentation: begin discussion of git-remote in user manual Start discussion of git-remote. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 5433d62..2fc8ce9 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -4,12 +4,12 @@ _________________ This manual is designed to be readable by someone with basic unix commandline skills, but no previous knowledge of git. -Chapters 1 and 2 explain how to fetch and study a project using git--the -tools you'd need to build and test a particular version of a software -project, to search for regressions, and so on. +Chapters 1 and 2 explain how to fetch and study a project using +git--the tools you'd need to build and test a particular version of a +software project, to search for regressions, and so on. -Chapter 3 explains how to do development with git and share your progress -with others. +Chapter 3 explains how to do development with git, and chapter 4 how +to share that development with others. Further chapters cover more specialized topics. @@ -50,7 +50,7 @@ directory, you will see that it contains a copy of the project files, together with a special top-level directory named ".git", which contains all the information about the history of the project. -In the following, examples will be taken from one of the two +In most of the following, examples will be taken from one of the two repositories above. How to check out a different version of a project @@ -340,9 +340,52 @@ remote-tracking branches to the latest version found in her repository. It will not touch any of your own branches--not even the "master" branch that was created for you on clone. +Fetching branches from other repositories +----------------------------------------- + +You can also track branches from repositories other than the one you +cloned from, using gitlink:git-remote[1]: + +------------------------------------------------- +$ git remote add linux-nfs git://linux-nfs.org/pub/nfs-2.6.git +$ git fetch +* refs/remotes/linux-nfs/master: storing branch 'master' ... + commit: bf81b46 +------------------------------------------------- + +New remote-tracking branches will be stored under the shorthand name +that you gave "git remote add", in this case linux-nfs: + +------------------------------------------------- +$ git branch -r +linux-nfs/master +origin/master +------------------------------------------------- + +If you run "git fetch " later, the tracking branches for the +named will be updated. + +If you examine the file .git/config, you will see that git has added +a new stanza: + +------------------------------------------------- +$ cat .git/config +... +[remote "linux-nfs"] + url = git://linux-nfs.org/~bfields/git.git + fetch = +refs/heads/*:refs/remotes/linux-nfs-read/* +... +------------------------------------------------- + +This is what causes git to track the remote's branches; you may +modify or delete these configuration options by editing .git/config +with a text editor. + Fetching individual branches ---------------------------- +TODO: find another home for this, later on: + You can also choose to update just one branch at a time: ------------------------------------------------- @@ -1618,9 +1661,9 @@ The basic requirements: knowledge than necessary: for example, "importing patches into a project" rather than "the git-am command" -Think about how to create a clear chapter dependency graph that will allow -people to get to important topics without necessarily reading everything -in between. +Think about how to create a clear chapter dependency graph that will +allow people to get to important topics without necessarily reading +everything in between. Scan Documentation/ for other stuff left out; in particular: howto's @@ -1634,11 +1677,8 @@ Scan email archives for other stuff left out Scan man pages to see if any assume more background than this manual provides. -Update git fetch discussion to use "git remote", move most of branch -discussion till later. - -Can also simplify beginning by suggesting disconnected head instead -of temporary branch creation. +Simplify beginning by suggesting disconnected head instead of temporary +branch creation. Explain how to refer to file stages in the "how to resolve a merge" section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The -- cgit v0.10.2-6-g49f6 From aec053bb0a1fb000622f51df22b2f18553a10efd Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 10 Jan 2007 23:17:00 -0500 Subject: Documentation: rev-list -> rev-parse, other typos, start examples Fix some typos, start adding some more simple examples. Signed-off-by: J. Bruce Fields diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 2fc8ce9..013e46f 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -622,7 +622,7 @@ We have seen several ways of naming commits already: - HEAD: refers to the head of the current branch There are many more; see the "SPECIFYING REVISION" section of the -gitlink:git-rev-list[1] man page for the complete list of ways to +gitlink:git-rev-parse[1] man page for the complete list of ways to name revisions. Some examples: ------------------------------------------------- @@ -663,6 +663,15 @@ When we discuss merges we'll also see the special name MERGE_HEAD, which refers to the other branch that we're merging in to the current branch. +The gitlink:git-rev-parse[1] command is a low-level command that is +occasionally useful for translating some name for a commit to the SHA1 id for +that commit: + +------------------------------------------------- +$ git rev-parse origin +e05db0fd4f31dde7005f075a84f96b360d05984b +------------------------------------------------- + Creating tags ------------- @@ -757,6 +766,47 @@ $ git show v2.5:fs/locks.c Before the colon may be anything that names a commit, and after it may be any path to a file tracked by git. +Examples +-------- + +Check whether two branches point at the same history +---------------------------------------------------- + +Suppose you want to check whether two branches point at the same point +in history. + +------------------------------------------------- +$ git diff origin..master +------------------------------------------------- + +will tell you whether the contents of the project are the same at the two +branches; in theory, however, it's possible that the same project contents +could have been arrived at by two different historical routes. You could +compare the SHA1 id's: + +------------------------------------------------- +$ git rev-list origin +e05db0fd4f31dde7005f075a84f96b360d05984b +$ git rev-list master +e05db0fd4f31dde7005f075a84f96b360d05984b +------------------------------------------------- + +Or you could recall that the ... operator selects all commits contained +reachable from either one reference or the other but not both: so + +------------------------------------------------- +$ git log origin...master +------------------------------------------------- + +will return no commits when the two branches are equal. + +Check which tagged version a given fix was first included in +------------------------------------------------------------ + +Suppose you know that a critical fix made it into the linux kernel with commit +e05db0fd... You'd like to find which kernel version that commit first made it +into. + Developing with git =================== @@ -1590,7 +1640,12 @@ mywork. The result will look like: In the process, it may discover conflicts. In that case it will stop and allow you to fix the conflicts as described in -"<>". Once the index is updated with +"<>". + +XXX: no, maybe not: git diff doesn't produce very useful results, and there's +no MERGE_HEAD. + +Once the index is updated with the results of the conflict resolution, instead of creating a new commit, just run -- cgit v0.10.2-6-g49f6 From eb6ae7f4ad565d56501e9e20a8bac5c579d50f84 Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Wed, 10 Jan 2007 18:11:53 -0800 Subject: User manual: fix typos in examples Correct command line examples of repo-config, format-patch and am. A full object name is 40-hexdigit; it may be 20-byte but 20-digit is misleading. Signed-off-by: Junio C Hamano diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 013e46f..7cd4dd6 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -161,7 +161,7 @@ index 8be626f..d7aac9d 100644 As you can see, a commit shows who made the latest change, what they did, and why. -Every commit has a 20-digit id, sometimes called the "SHA1 id", shown +Every commit has a 40-hexdigit id, sometimes called the "SHA1 id", shown on the first line of the "git show" output. You can usually refer to a commit by a shorter name, such as a tag or a branch name, but this longer id can also be useful. In particular, it is a globally unique @@ -486,7 +486,7 @@ create similar configuration options to save typing; for example, after ------------------------------------------------- -$ git repo-config remote.example.url=git://example.com/proj.git +$ git repo-config remote.example.url git://example.com/proj.git ------------------------------------------------- then the following two commands will do the same thing: @@ -499,7 +499,7 @@ $ git fetch example master:refs/remotes/example/master Even better, if you add one more option: ------------------------------------------------- -$ git repo-config remote.example.fetch=master:refs/remotes/example/master +$ git repo-config remote.example.fetch master:refs/remotes/example/master ------------------------------------------------- then the following commands will all do the same thing: @@ -514,7 +514,7 @@ $ git fetch example You can also add a "+" to force the update each time: ------------------------------------------------- -$ git repo-config +master:ref/remotes/example/master +$ git repo-config remote.example.fetch +master:ref/remotes/example/master ------------------------------------------------- Don't do this unless you're sure you won't mind "git fetch" possibly @@ -613,7 +613,7 @@ Naming commits We have seen several ways of naming commits already: - - 20-digit SHA1 id + - 40-hexdigit SHA1 id - branch name: refers to the commit at the head of the given branch - tag name: refers to the commit pointed to by the given tag @@ -621,7 +621,7 @@ We have seen several ways of naming commits already: <>). - HEAD: refers to the head of the current branch -There are many more; see the "SPECIFYING REVISION" section of the +There are many more; see the "SPECIFYING REVISIONS" section of the gitlink:git-rev-parse[1] man page for the complete list of ways to name revisions. Some examples: @@ -867,6 +867,14 @@ By default, the content of the index is identical to that of the HEAD. The command "git diff --cached" shows the difference between HEAD and the index, so you should no output from that command. +//////////////////////////////////////////////// + +This is talking about not "by default", but "when you start +out". The last sentence does not parse for me... + +//////////////////////////////////////////////// + + Modifying the index is easy: To update the index with the new contents of a modified file, use @@ -881,8 +889,7 @@ To add the contents of a new file to the index, use $ git add path/to/file ------------------------------------------------- -To remove a file from the index that you've removed from the working -tree, +To remove a file from the index and from the working tree, ------------------------------------------------- $ git rm path/to/file @@ -1306,7 +1313,7 @@ just be to send them as patches in email: First, use gitlink:git-format-patches[1]; for example: ------------------------------------------------- -$ git format-patches origin +$ git format-patch origin ------------------------------------------------- will produce a numbered series of files in the current directory, one @@ -1327,9 +1334,18 @@ Just save all of the patch-containing messages, in order, into a single mailbox file, say "patches.mbox", then run ------------------------------------------------- -$ git am patches.mbox +$ git am -3 patches.mbox ------------------------------------------------- +//////////////////////////////////////////////// + +If you allow git-am to fall back to 3-way merge with -3, you +would see conflicts and "resolving a merge" techniques apply. +Otherwise "conflicts" will just fail the patch and your working +tree and index are left untouched. + +//////////////////////////////////////////////// + Git will apply each patch in order; if any conflicts are found, it will stop, and you can fix the conflicts as described in "<>". Once the index is updated -- cgit v0.10.2-6-g49f6 From 01997b4a256ed7ef96ede527a92eeeecc243a927 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 10 Jan 2007 23:23:37 -0500 Subject: user manual: answer some comments from Junio Junio left a few comments in his previous patch; deal with each of them. Signed-off-by: J. Bruce Fields diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 7cd4dd6..ae21ef2 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -863,17 +863,10 @@ times as you want: in order to keep track of what you want committed at step 3, git maintains a snapshot of the tree's contents in a special staging area called "the index." -By default, the content of the index is identical to that of the -HEAD. The command "git diff --cached" shows the difference between -HEAD and the index, so you should no output from that command. - -//////////////////////////////////////////////// - -This is talking about not "by default", but "when you start -out". The last sentence does not parse for me... - -//////////////////////////////////////////////// - +At the beginning, the content of the index will be identical to +that of the HEAD. The command "git diff --cached", which shows +the difference between the HEAD and the index, should therefore +produce no output at that point. Modifying the index is easy: @@ -1337,20 +1330,14 @@ single mailbox file, say "patches.mbox", then run $ git am -3 patches.mbox ------------------------------------------------- -//////////////////////////////////////////////// - -If you allow git-am to fall back to 3-way merge with -3, you -would see conflicts and "resolving a merge" techniques apply. -Otherwise "conflicts" will just fail the patch and your working -tree and index are left untouched. - -//////////////////////////////////////////////// - Git will apply each patch in order; if any conflicts are found, it will stop, and you can fix the conflicts as described in -"<>". Once the index is updated -with the results of the conflict resolution, instead of creating a -new commit, just run +"<>". (The "-3" option tells +git to perform a merge; if you would prefer it just to abort and +leave your tree and index untouched, you may omit that option.) + +Once the index is updated with the results of the conflict +resolution, instead of creating a new commit, just run ------------------------------------------------- $ git am --resolved -- cgit v0.10.2-6-g49f6 From f1d2b47794bc0425f817b9015ad738f2cfb7f3f3 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Thu, 11 Jan 2007 12:44:08 -0500 Subject: user-manual: replace init-db by init Replace mentions of init-db by mentions of init. Signed-off-by: J. Bruce Fields diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index ae21ef2..94c09e5 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -833,7 +833,7 @@ Creating a new repository from scratch is very easy: ------------------------------------------------- $ mkdir project $ cd project -$ git init-db +$ git init ------------------------------------------------- If you have some initial content (say, a tarball): @@ -841,7 +841,7 @@ If you have some initial content (say, a tarball): ------------------------------------------------- $ tar -xzvf project.tar.gz $ cd project -$ git init-db +$ git init $ git add . # include everything below ./ in the first commit: $ git commit ------------------------------------------------- -- cgit v0.10.2-6-g49f6 From 69f7ad730a21eb7e8aeb22b2ee76856dff2b7bd2 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 14 Jan 2007 16:29:40 -0500 Subject: user-manual: reindent Just some minor reindenting Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 94c09e5..eeec2cd 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -779,10 +779,10 @@ in history. $ git diff origin..master ------------------------------------------------- -will tell you whether the contents of the project are the same at the two -branches; in theory, however, it's possible that the same project contents -could have been arrived at by two different historical routes. You could -compare the SHA1 id's: +will tell you whether the contents of the project are the same at the +two branches; in theory, however, it's possible that the same project +contents could have been arrived at by two different historical +routes. You could compare the SHA1 id's: ------------------------------------------------- $ git rev-list origin @@ -791,8 +791,9 @@ $ git rev-list master e05db0fd4f31dde7005f075a84f96b360d05984b ------------------------------------------------- -Or you could recall that the ... operator selects all commits contained -reachable from either one reference or the other but not both: so +Or you could recall that the ... operator selects all commits +contained reachable from either one reference or the other but not +both: so ------------------------------------------------- $ git log origin...master @@ -803,9 +804,21 @@ will return no commits when the two branches are equal. Check which tagged version a given fix was first included in ------------------------------------------------------------ -Suppose you know that a critical fix made it into the linux kernel with commit -e05db0fd... You'd like to find which kernel version that commit first made it -into. +Suppose you know that the commit e05db0fd fixed a certain problem. +You'd like to find the earliest tagged release that contains that +fix. + +Of course, there may be more than one answer--if the history branched +after commit e05db0fd, then there could be multiple "earliest" tagged +releases. + +You could just visually inspect the commits since e05db0fd: + +------------------------------------------------- +$ gitk e05db0fd.. +------------------------------------------------- + +... Developing with git =================== -- cgit v0.10.2-6-g49f6 From 2f99710cfe2aacce077c510f93b51edd9ba16a0d Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 14 Jan 2007 22:43:47 -0500 Subject: user-manual: rewrap, fix heading levels Fix some heading levels that prevented compile; rewrap some stuff. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index eeec2cd..369cdad 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -770,7 +770,7 @@ Examples -------- Check whether two branches point at the same history ----------------------------------------------------- +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose you want to check whether two branches point at the same point in history. @@ -802,7 +802,7 @@ $ git log origin...master will return no commits when the two branches are equal. Check which tagged version a given fix was first included in ------------------------------------------------------------- +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose you know that the commit e05db0fd fixed a certain problem. You'd like to find the earliest tagged release that contains that @@ -1723,14 +1723,15 @@ Notes and todo list for this manual This is a work in progress. The basic requirements: - - It must be readable in order, from beginning to end, by someone - intelligent with a basic grasp of the unix commandline, but - without any special knowledge of git. If necessary, any other - prerequisites should be specifically mentioned as they arise. - - Whenever possible, section headings should clearly describe the - task they explain how to do, in language that requires no more - knowledge than necessary: for example, "importing patches into a - project" rather than "the git-am command" + - It must be readable in order, from beginning to end, by + someone intelligent with a basic grasp of the unix + commandline, but without any special knowledge of git. If + necessary, any other prerequisites should be specifically + mentioned as they arise. + - Whenever possible, section headings should clearly describe + the task they explain how to do, in language that requires + no more knowledge than necessary: for example, "importing + patches into a project" rather than "the git-am command" Think about how to create a clear chapter dependency graph that will allow people to get to important topics without necessarily reading @@ -1748,20 +1749,25 @@ Scan email archives for other stuff left out Scan man pages to see if any assume more background than this manual provides. -Simplify beginning by suggesting disconnected head instead of temporary -branch creation. +Simplify beginning by suggesting disconnected head instead of +temporary branch creation. Explain how to refer to file stages in the "how to resolve a merge" section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The -"git ls-files --unmerged --stage" thing is sorta useful too, actually. And -note gitk --merge. Also what's easiest way to see common merge base? +"git ls-files --unmerged --stage" thing is sorta useful too, +actually. And note gitk --merge. Also what's easiest way to see +common merge base? Note also text where I claim rebase and am +conflicts are resolved like merges isn't generally true, at least by +default--fix. -Add more good examples. Entire sections of just cookbook examples might -be a good idea; maybe make an "advanced examples" section a standard -end-of-chapter section? +Add more good examples. Entire sections of just cookbook examples +might be a good idea; maybe make an "advanced examples" section a +standard end-of-chapter section? Include cross-references to the glossary, where appropriate. +Add quickstart as first chapter. + To document: reflogs, git reflog expire shallow clones?? See draft 1.5.0 release notes for some documentation. -- cgit v0.10.2-6-g49f6 From ef89f701a0c214fa2967e921f8d3891e25cf3125 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sat, 20 Jan 2007 21:41:48 -0500 Subject: user-manual: add "quick start" as chapter 1 Add a "quick start" guide, modelled after Mercurial's, as the first chapter. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 369cdad..df0f762 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -4,11 +4,14 @@ _________________ This manual is designed to be readable by someone with basic unix commandline skills, but no previous knowledge of git. -Chapters 1 and 2 explain how to fetch and study a project using +Chapter 1 gives a brief overview of git commands, without any +explanation; you can skip to chapter 2 on a first reading. + +Chapters 2 and 3 explain how to fetch and study a project using git--the tools you'd need to build and test a particular version of a software project, to search for regressions, and so on. -Chapter 3 explains how to do development with git, and chapter 4 how +Chapter 4 explains how to do development with git, and chapter 5 how to share that development with others. Further chapters cover more specialized topics. @@ -20,6 +23,201 @@ pages. For a command such as "git clone", just use $ man git-clone ------------------------------------------------ +Git Quick Start +=============== + +This is a quick summary of the major commands; the following chapters +will explain how these work in more detail. + +Creating a new repository +------------------------- + +From a tarball: + +----------------------------------------------- +$ tar xzf project.tar.gz +$ cd project +$ git init +Initialized empty Git repository in .git/ +$ git add . +$ git commit +----------------------------------------------- + +From a remote repository: + +----------------------------------------------- +$ git clone git://example.com/pub/project.git +$ cd project +----------------------------------------------- + +Managing branches +----------------- + +----------------------------------------------- +$ git branch # list all branches in this repo +$ git checkout test # switch working directory to branch "test" +$ git branch new # create branch "new" starting at current HEAD +$ git branch -d new # delete branch "new" +----------------------------------------------- + +Instead of basing new branch on current HEAD (the default), use: + +----------------------------------------------- +$ git branch new test # branch named "test" +$ git branch new v2.6.15 # tag named v2.6.15 +$ git branch new HEAD^ # commit before the most recent +$ git branch new HEAD^^ # commit before that +$ git branch new test~10 # ten commits before tip of branch "test" +----------------------------------------------- + +Create and switch to a new branch at the same time: + +----------------------------------------------- +$ git checkout -b new v2.6.15 +----------------------------------------------- + +Update and examine branches from the repository you cloned from: + +----------------------------------------------- +$ git fetch # update +$ git branch -r # list + origin/master + origin/next + ... +$ git branch checkout -b masterwork origin/master +----------------------------------------------- + +Fetch a branch from a different repository, and give it a new +name in your repository: + +----------------------------------------------- +$ git fetch git://example.com/project.git theirbranch:mybranch +$ git fetch git://example.com/project.git v2.6.15:mybranch +----------------------------------------------- + +Keep a list of repositories you work with regularly: + +----------------------------------------------- +$ git remote add example git://example.com/project.git +$ git remote # list remote repositories +example +origin +$ git remote show example # get details +* remote example + URL: git://example.com/project.git + Tracked remote branches + master next ... +$ git fetch example # update branches from example +$ git branch -r # list all remote branches +----------------------------------------------- + + +Exploring history +----------------- + +----------------------------------------------- +$ gitk # visualize and browse history +$ git log # list all commits +$ git log src/ # ...modifying src/ +$ git log v2.6.15..v2.6.16 # ...in v2.6.16, not in v2.6.15 +$ git log master..test # ...in branch test, not in branch master +$ git log test..master # ...in branch master, but not in test +$ git log test...master # ...in one branch, not in both +$ git log -S'foo()' # ...where difference contain "foo()" +$ git log --since="2 weeks ago" +$ git log -p # show patches as well +$ git show # most recent commit +$ git diff v2.6.15..v2.6.16 # diff between two tagged versions +$ git diff v2.6.15..HEAD # diff with current head +$ git grep "foo()" # search working directory for "foo()" +$ git grep v2.6.15 "foo()" # search old tree for "foo()" +$ git show v2.6.15:a.txt # look at old version of a.txt +----------------------------------------------- + +Searching for regressions: + +----------------------------------------------- +$ git bisect start +$ git bisect bad # current version is bad +$ git bisect good v2.6.13-rc2 # last known good revision +Bisecting: 675 revisions left to test after this + # test here, then: +$ git bisect good # if this revision is good, or +$ git bisect bad # if this revision is bad. + # repeat until done. +----------------------------------------------- + +Making changes +-------------- + +Make sure git knows who to blame: + +------------------------------------------------ +$ cat >~/.gitconfig <<\EOF +[user] +name = Your Name Comes Here +email = you@yourdomain.example.com +EOF +------------------------------------------------ + +Select file contents to include in the next commit, then make the +commit: + +----------------------------------------------- +$ git add a.txt # updated file +$ git add b.txt # new file +$ git rm c.txt # old file +$ git commit +----------------------------------------------- + +Or, prepare and create the commit in one step: + +----------------------------------------------- +$ git commit d.txt # use latest content of d.txt +$ git commit -a # use latest content of all tracked files +----------------------------------------------- + +Merging +------- + +----------------------------------------------- +$ git merge test # merge branch "test" into the current branch +$ git pull git://example.com/project.git master + # fetch and merge in remote branch +$ git pull . test # equivalent to git merge test +----------------------------------------------- + +Sharing development +------------------- + +Importing or exporting patches: + +----------------------------------------------- +$ git format-patch origin..HEAD # format a patch for each commit + # in HEAD but not in origin +$ git-am mbox # import patches from the mailbox "mbox" +----------------------------------------------- + +Fetch a branch from a different git repository: + +----------------------------------------------- +$ git fetch git://example.com/project.git theirbranch:mybranch +----------------------------------------------- + +Fetch a branch in a different git repository, then merge into the +current branch: + +----------------------------------------------- +$ git pull git://example.com/project.git theirbranch +----------------------------------------------- + +Store the fetched branch into a local branch before merging into the +current branch: + +----------------------------------------------- +$ git pull git://example.com/project.git theirbranch:mybranch +----------------------------------------------- + Repositories and Branches ========================= -- cgit v0.10.2-6-g49f6 From e4add70cd4ce287c9866f7eec5f1e42245e6f846 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 21 Jan 2007 22:02:34 -0500 Subject: user-manual: minor quickstart reorganization Move around some stuff in the quickstart, add "push" examples. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index df0f762..3f23181 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -187,8 +187,8 @@ $ git pull git://example.com/project.git master $ git pull . test # equivalent to git merge test ----------------------------------------------- -Sharing development -------------------- +Sharing your changes +-------------------- Importing or exporting patches: @@ -198,12 +198,6 @@ $ git format-patch origin..HEAD # format a patch for each commit $ git-am mbox # import patches from the mailbox "mbox" ----------------------------------------------- -Fetch a branch from a different git repository: - ------------------------------------------------ -$ git fetch git://example.com/project.git theirbranch:mybranch ------------------------------------------------ - Fetch a branch in a different git repository, then merge into the current branch: @@ -218,6 +212,26 @@ current branch: $ git pull git://example.com/project.git theirbranch:mybranch ----------------------------------------------- +After creating commits on a local branch, update the remote +branch with your commits: + +----------------------------------------------- +$ git push ssh://example.com/project.git mybranch:theirbranch +----------------------------------------------- + +When remote and local branch are both named "test": + +----------------------------------------------- +$ git push ssh://example.com/project.git test +----------------------------------------------- + +Shortcut version for a frequently used remote repository: + +----------------------------------------------- +$ git remote add example ssh://example.com/project.git +$ git push example test +----------------------------------------------- + Repositories and Branches ========================= -- cgit v0.10.2-6-g49f6 From fe4b3e591bdfe580cfc716653dd5ac2105d23f8a Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 21 Jan 2007 22:14:39 -0500 Subject: user-manual: clarify difference between tag and branch Explain the difference (well, one of the differences) between a tag and a branch. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 3f23181..267bbd7 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -304,6 +304,9 @@ v2.6.13 ... ------------------------------------------------ +Tags are expected to always point at the same version of a project, +while branches are expected to advance as development progresses. + Create a new branch pointing to one of these versions and check it out using gitlink:git-checkout[1]: -- cgit v0.10.2-6-g49f6 From f60b964249fb38fea7906559875c600665a2d991 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 21 Jan 2007 22:31:07 -0500 Subject: user-manual: update references discussion Since references may be packed, it's no longer as helpful to introduce references as paths relative to .git. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 267bbd7..6c858aa 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -506,41 +506,33 @@ Note that the name "origin" is just the name that git uses by default to refer to the repository that you cloned from. [[how-git-stores-references]] -How git stores references -------------------------- +Naming branches, tags, and other references +------------------------------------------- Branches, remote-tracking branches, and tags are all references to -commits. Git stores these references in the ".git" directory. Most -of them are stored in .git/refs/: - - - branches are stored in .git/refs/heads - - tags are stored in .git/refs/tags - - remote-tracking branches for "origin" are stored in - .git/refs/remotes/origin/ +commits. All references are named with a slash-separated path name +starting with "refs"; the names we've been using so far are actually +shorthand: -If you look at one of these files you will see that they usually -contain just the SHA1 id of a commit: + - The branch "test" is short for "refs/heads/test". + - The tag "v2.6.18" is short for "refs/tags/v2.6.18". + - "origin/master" is short for "refs/remotes/origin/master". ------------------------------------------------- -$ ls .git/refs/heads/ -master -$ cat .git/refs/heads/master -c0f982dcf188d55db9d932a39d4ea7becaa55fed ------------------------------------------------- +The full name is occasionally useful if, for example, there ever +exists a tag and a branch with the same name. -You can refer to a reference by its path relative to the .git -directory. However, we've seen above that git will also accept -shorter names; for example, "master" is an acceptable shortcut for -"refs/heads/master", and "origin/master" is a shortcut for -"refs/remotes/origin/master". +As another useful shortcut, if the repository "origin" posesses only +a single branch, you can refer to that branch as just "origin". -As another useful shortcut, you can also refer to the "HEAD" of -"origin" (or any other remote), using just the name of the remote. +More generally, if you have defined a remote repository named +"example", you can refer to the branch in that repository as +"example". And for a repository with multiple branches, this will +refer to the branch designated as the "HEAD" branch. For the complete list of paths which git checks for references, and -how it decides which to choose when there are multiple references -with the same name, see the "SPECIFYING REVISIONS" section of -gitlink:git-rev-parse[1]. +the order it uses to decide which to choose when there are multiple +references with the same shorthand name, see the "SPECIFYING +REVISIONS" section of gitlink:git-rev-parse[1]. [[Updating-a-repository-with-git-fetch]] Updating a repository with git fetch -- cgit v0.10.2-6-g49f6 From 17217090cf92e094f711359d92196e8129e3281c Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 21 Jan 2007 23:03:36 -0500 Subject: user-manual: update git-gc discussion It appears git-gc will no longer prune automatically, so we don't need to tell people not to do other stuff while running it. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 6c858aa..30adc72 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1447,16 +1447,14 @@ On large repositories, git depends on compression to keep the history information from taking up to much space on disk or in memory. This compression is not performed automatically. Therefore you -should occasionally run +should occasionally run gitlink:git-gc[1]: ------------------------------------------------- $ git gc ------------------------------------------------- -to recompress the archive and to prune any commits which are no -longer referred to anywhere. This can be very time-consuming, and -you should not modify the repository while it is working, so you -should run it while you are not working. +to recompress the archive. This can be very time-consuming, so +you may prefer to run git-gc when you are not doing other work. Sharing development with others =============================== -- cgit v0.10.2-6-g49f6 From 11e016a32c1ac5535a9a248e23bc9a7e1f6c43d2 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Fri, 26 Jan 2007 00:17:12 -0500 Subject: user-manual: stub discussion of fsck and reflog Have some sort of recovery/reliability section that deals with reflog and fsck. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 30adc72..00e445d 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1456,6 +1456,27 @@ $ git gc to recompress the archive. This can be very time-consuming, so you may prefer to run git-gc when you are not doing other work. +Ensuring reliability +-------------------- + +Checking the repository for corruption +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +TODO: + git-fsck + "dangling objects" explanation + Brief explanation here, + include forward reference to longer explanation from + Linus, to be added to later chapter + +Recovering lost changes +~~~~~~~~~~~~~~~~~~~~~~~ + +TODO: + reflog + git-fsck + low-level examination of objects + Sharing development with others =============================== -- cgit v0.10.2-6-g49f6 From b181d57ff40d94799a595045718039dc9d4320f7 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sat, 27 Jan 2007 01:03:07 -0500 Subject: user-manual: reorganize fetch discussion, add internals, etc. Keep git remote discussion in the first chapter, but postpone lower-level git fetch usage (to fetch individual branches) till later. Import a bunch of slightly modified text from the readme to give an architectural overview at the end. Add more discussion of history rewriting. And a bunch of other miscellaneous changes.... Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 00e445d..87c605f 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -5,7 +5,7 @@ This manual is designed to be readable by someone with basic unix commandline skills, but no previous knowledge of git. Chapter 1 gives a brief overview of git commands, without any -explanation; you can skip to chapter 2 on a first reading. +explanation; you may prefer to skip to chapter 2 on a first reading. Chapters 2 and 3 explain how to fetch and study a project using git--the tools you'd need to build and test a particular version of a @@ -99,16 +99,16 @@ Keep a list of repositories you work with regularly: ----------------------------------------------- $ git remote add example git://example.com/project.git -$ git remote # list remote repositories +$ git remote # list remote repositories example origin -$ git remote show example # get details +$ git remote show example # get details * remote example URL: git://example.com/project.git Tracked remote branches master next ... -$ git fetch example # update branches from example -$ git branch -r # list all remote branches +$ git fetch example # update branches from example +$ git branch -r # list all remote branches ----------------------------------------------- @@ -134,7 +134,7 @@ $ git grep v2.6.15 "foo()" # search old tree for "foo()" $ git show v2.6.15:a.txt # look at old version of a.txt ----------------------------------------------- -Searching for regressions: +Search for regressions: ----------------------------------------------- $ git bisect start @@ -173,7 +173,7 @@ $ git commit Or, prepare and create the commit in one step: ----------------------------------------------- -$ git commit d.txt # use latest content of d.txt +$ git commit d.txt # use latest content only of d.txt $ git commit -a # use latest content of all tracked files ----------------------------------------------- @@ -232,6 +232,21 @@ $ git remote add example ssh://example.com/project.git $ git push example test ----------------------------------------------- +Repository maintenance +---------------------- + +Check for corruption: + +----------------------------------------------- +$ git fsck-objects +----------------------------------------------- + +Recompress, remove unused cruft: + +----------------------------------------------- +$ git gc +----------------------------------------------- + Repositories and Branches ========================= @@ -376,13 +391,15 @@ index 8be626f..d7aac9d 100644 As you can see, a commit shows who made the latest change, what they did, and why. -Every commit has a 40-hexdigit id, sometimes called the "SHA1 id", shown -on the first line of the "git show" output. You can usually refer to -a commit by a shorter name, such as a tag or a branch name, but this -longer id can also be useful. In particular, it is a globally unique -name for this commit: so if you tell somebody else the SHA1 id (for -example in email), then you are guaranteed they will see the same -commit in their repository that you do in yours. +Every commit has a 40-hexdigit id, sometimes called the "object name" +or the "SHA1 id", shown on the first line of the "git show" output. +You can usually refer to a commit by a shorter name, such as a tag or a +branch name, but this longer name can also be useful. Most +importantly, it is a globally unique name for this commit: so if you +tell somebody else the object name (for example in email), then you are +guaranteed that name will refer to the same commit in their repository +that you it does in yours (assuming their repository has that commit at +all). Understanding history: commits, parents, and reachability ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -588,152 +605,6 @@ This is what causes git to track the remote's branches; you may modify or delete these configuration options by editing .git/config with a text editor. -Fetching individual branches ----------------------------- - -TODO: find another home for this, later on: - -You can also choose to update just one branch at a time: - -------------------------------------------------- -$ git fetch origin todo:refs/remotes/origin/todo -------------------------------------------------- - -The first argument, "origin", just tells git to fetch from the -repository you originally cloned from. The second argument tells git -to fetch the branch named "todo" from the remote repository, and to -store it locally under the name refs/remotes/origin/todo; as we saw -above, remote-tracking branches are stored under -refs/remotes//. - -You can also fetch branches from other repositories; so - -------------------------------------------------- -$ git fetch git://example.com/proj.git master:refs/remotes/example/master -------------------------------------------------- - -will create a new reference named "refs/remotes/example/master" and -store in it the branch named "master" from the repository at the -given URL. If you already have a branch named -"refs/remotes/example/master", it will attempt to "fast-forward" to -the commit given by example.com's master branch. So next we explain -what a fast-forward is: - -[[fast-forwards]] -Understanding git history: fast-forwards ----------------------------------------- - -In the previous example, when updating an existing branch, "git -fetch" checks to make sure that the most recent commit on the remote -branch is a descendant of the most recent commit on your copy of the -branch before updating your copy of the branch to point at the new -commit. Git calls this process a "fast forward". - -A fast forward looks something like this: - - o--o--o--o <-- old head of the branch - \ - o--o--o <-- new head of the branch - - -In some cases it is possible that the new head will *not* actually be -a descendant of the old head. For example, the developer may have -realized she made a serious mistake, and decided to backtrack, -resulting in a situation like: - - o--o--o--o--a--b <-- old head of the branch - \ - o--o--o <-- new head of the branch - - - -In this case, "git fetch" will fail, and print out a warning. - -In that case, you can still force git to update to the new head, as -described in the following section. However, note that in the -situation above this may mean losing the commits labeled "a" and "b", -unless you've already created a reference of your own pointing to -them. - -Forcing git fetch to do non-fast-forward updates ------------------------------------------------- - -If git fetch fails because the new head of a branch is not a -descendant of the old head, you may force the update with: - -------------------------------------------------- -$ git fetch git://example.com/proj.git +master:refs/remotes/example/master -------------------------------------------------- - -Note the addition of the "+" sign. Be aware that commits which the -old version of example/master pointed at may be lost, as we saw in -the previous section. - -Configuring remote branches ---------------------------- - -We saw above that "origin" is just a shortcut to refer to the -repository which you originally cloned from. This information is -stored in git configuration variables, which you can see using -gitlink:git-repo-config[1]: - -------------------------------------------------- -$ git-repo-config -l -core.repositoryformatversion=0 -core.filemode=true -core.logallrefupdates=true -remote.origin.url=git://git.kernel.org/pub/scm/git/git.git -remote.origin.fetch=+refs/heads/*:refs/remotes/origin/* -branch.master.remote=origin -branch.master.merge=refs/heads/master -------------------------------------------------- - -If there are other repositories that you also use frequently, you can -create similar configuration options to save typing; for example, -after - -------------------------------------------------- -$ git repo-config remote.example.url git://example.com/proj.git -------------------------------------------------- - -then the following two commands will do the same thing: - -------------------------------------------------- -$ git fetch git://example.com/proj.git master:refs/remotes/example/master -$ git fetch example master:refs/remotes/example/master -------------------------------------------------- - -Even better, if you add one more option: - -------------------------------------------------- -$ git repo-config remote.example.fetch master:refs/remotes/example/master -------------------------------------------------- - -then the following commands will all do the same thing: - -------------------------------------------------- -$ git fetch git://example.com/proj.git master:ref/remotes/example/master -$ git fetch example master:ref/remotes/example/master -$ git fetch example example/master -$ git fetch example -------------------------------------------------- - -You can also add a "+" to force the update each time: - -------------------------------------------------- -$ git repo-config remote.example.fetch +master:ref/remotes/example/master -------------------------------------------------- - -Don't do this unless you're sure you won't mind "git fetch" possibly -throwing away commits on mybranch. - -Also note that all of the above configuration can be performed by -directly editing the file .git/config instead of using -gitlink:git-repo-config[1]. - -See gitlink:git-repo-config[1] for more details on the configuration -options mentioned above. - Exploring git history ===================== @@ -1008,8 +879,8 @@ $ git log origin...master will return no commits when the two branches are equal. -Check which tagged version a given fix was first included in -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Find first tagged version including a given fix +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose you know that the commit e05db0fd fixed a certain problem. You'd like to find the earliest tagged release that contains that @@ -1025,7 +896,47 @@ You could just visually inspect the commits since e05db0fd: $ gitk e05db0fd.. ------------------------------------------------- -... +Or you can use gitlink:git-name-rev[1], which will give the commit a +name based on any tag it finds pointing to one of the commit's +descendants: + +------------------------------------------------- +$ git name-rev e05db0fd +e05db0fd tags/v1.5.0-rc1^0~23 +------------------------------------------------- + +The gitlink:git-describe[1] command does the opposite, naming the +revision using a tag on which the given commit is based: + +------------------------------------------------- +$ git describe e05db0fd +v1.5.0-rc0-ge05db0f +------------------------------------------------- + +but that may sometimes help you guess which tags might come after the +given commit. + +If you just want to verify whether a given tagged version contains a +given commit, you could use gitlink:git-merge-base[1]: + +------------------------------------------------- +$ git merge-base e05db0fd v1.5.0-rc1 +e05db0fd4f31dde7005f075a84f96b360d05984b +------------------------------------------------- + +The merge-base command finds a common ancestor of the given commits, +and always returns one or the other in the case where one is a +descendant of the other; so the above output shows that e05db0fd +actually is an ancestor of v1.5.0-rc1. + +Alternatively, note that + +------------------------------------------------- +$ git log v1.5.0-rc1..305db0fd +------------------------------------------------- + +will produce empty output if and only if v1.5.0-rc1 includes 305db0fd, +because it outputs only commits that are not reachable from v1.5.0-rc1. Developing with git =================== @@ -1775,7 +1686,7 @@ TODO: topic branches, typical roles as in everyday.txt, ? Working with other version control systems ========================================== -TODO: CVS, Subversion, series-of-release-tarballs, ? +TODO: CVS, Subversion, series-of-release-tarballs, etc. [[cleaning-up-history]] Rewriting history and maintaining patch series @@ -1796,8 +1707,8 @@ complicated feature, and to present it to the other developers in a way that makes it easy for them to read your changes, verify that they are correct, and understand why you made each change. -If you present all of your changes as a single patch (or commit), they may -find it is too much to digest all at once. +If you present all of your changes as a single patch (or commit), they +may find it is too much to digest all at once. If you present them with the entire history of your work, complete with mistakes, corrections, and dead ends, they may be overwhelmed. @@ -1816,9 +1727,9 @@ So the ideal is usually to produce a series of patches such that: 4. The complete series produces the same end result as your own (probably much messier!) development process did. -We will introduce some tools that can help you do this, explain how to use -them, and then explain some of the problems that can arise because you are -rewriting history. +We will introduce some tools that can help you do this, explain how to +use them, and then explain some of the problems that can arise because +you are rewriting history. Keeping a patch series up to date using git-rebase -------------------------------------------------- @@ -1826,8 +1737,8 @@ Keeping a patch series up to date using git-rebase Suppose you have a series of commits in a branch "mywork", which originally branched off from "origin". -Suppose you create a branch "mywork" on a remote-tracking branch "origin", -and created some commits on top of it: +Suppose you create a branch "mywork" on a remote-tracking branch +"origin", and created some commits on top of it: ------------------------------------------------- $ git checkout -b mywork origin @@ -1870,26 +1781,20 @@ $ git checkout mywork $ git rebase origin ------------------------------------------------- -This will remove each of your commits from mywork, temporarily saving them -as patches (in a directory named ".dotest"), update mywork to point at the -latest version of origin, then apply each of the saved patches to the new -mywork. The result will look like: +This will remove each of your commits from mywork, temporarily saving +them as patches (in a directory named ".dotest"), update mywork to +point at the latest version of origin, then apply each of the saved +patches to the new mywork. The result will look like: o--o--O--o--o--o <-- origin \ a'--b'--c' <-- mywork -In the process, it may discover conflicts. In that case it will stop and -allow you to fix the conflicts as described in -"<>". - -XXX: no, maybe not: git diff doesn't produce very useful results, and there's -no MERGE_HEAD. - -Once the index is updated with -the results of the conflict resolution, instead of creating a new commit, -just run +In the process, it may discover conflicts. In that case it will stop +and allow you to fix the conflicts; after fixing conflicts, use "git +add" to update the index with those contents, and then, instead of +running git-commit, just run ------------------------------------------------- $ git rebase --continue @@ -1907,36 +1812,886 @@ $ git rebase --abort Reordering or selecting from a patch series ------------------------------------------- -Given one existing commit, the gitlink:git-cherry-pick[1] command allows -you to apply the change introduced by that commit and create a new commit -that records it. +Given one existing commit, the gitlink:git-cherry-pick[1] command +allows you to apply the change introduced by that commit and create a +new commit that records it. So, for example, if "mywork" points to a +series of patches on top of "origin", you might do something like: + +------------------------------------------------- +$ git checkout -b mywork-new origin +$ gitk origin..mywork & +------------------------------------------------- + +And browse through the list of patches in the mywork branch using gitk, +applying them (possibly in a different order) to mywork-new using +cherry-pick, and possibly modifying them as you go using commit +--amend. + +Another technique is to use git-format-patch to create a series of +patches, then reset the state to before the patches: -This can be useful for modifying a patch series. +------------------------------------------------- +$ git format-patch origin +$ git reset --hard origin +------------------------------------------------- -TODO: elaborate +Then modify, reorder, or eliminate patches as preferred before applying +them again with gitlink:git-am[1]. Other tools ----------- -There are numerous other tools, such as stgit, which exist for the purpose -of maintianing a patch series. These are out of the scope of this manual. +There are numerous other tools, such as stgit, which exist for the +purpose of maintaining a patch series. These are out of the scope of +this manual. Problems with rewriting history ------------------------------- -The primary problem with rewriting the history of a branch has to do with -merging. +The primary problem with rewriting the history of a branch has to do +with merging. Suppose somebody fetches your branch and merges it into +their branch, with a result something like this: + + o--o--O--o--o--o <-- origin + \ \ + t--t--t--m <-- their branch: + +Then suppose you modify the last three commits: + + o--o--o <-- new head of origin + / + o--o--O--o--o--o <-- old head of origin + +If we examined all this history together in one repository, it will +look like: + + o--o--o <-- new head of origin + / + o--o--O--o--o--o <-- old head of origin + \ \ + t--t--t--m <-- their branch: + +Git has no way of knowing that the new head is an updated version of +the old head; it treats this situation exactly the same as it would if +two developers had independently done the work on the old and new heads +in parallel. At this point, if someone attempts to merge the new head +in to their branch, git will attempt to merge together the two (old and +new) lines of development, instead of trying to replace the old by the +new. The results are likely to be unexpected. + +You may still choose to publish branches whose history is rewritten, +and it may be useful for others to be able to fetch those branches in +order to examine or test them, but they should not attempt to pull such +branches into their own work. + +For true distributed development that supports proper merging, +published branches should never be rewritten. + +Advanced branch management +========================== -TODO: elaborate +Fetching individual branches +---------------------------- + +Instead of using gitlink:git-remote[1], you can also choose just +to update one branch at a time, and to store it locally under an +arbitrary name: + +------------------------------------------------- +$ git fetch origin todo:my-todo-work +------------------------------------------------- + +The first argument, "origin", just tells git to fetch from the +repository you originally cloned from. The second argument tells git +to fetch the branch named "todo" from the remote repository, and to +store it locally under the name refs/heads/my-todo-work. + +You can also fetch branches from other repositories; so + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:example-master +------------------------------------------------- + +will create a new branch named "example-master" and store in it the +branch named "master" from the repository at the given URL. If you +already have a branch named example-master, it will attempt to +"fast-forward" to the commit given by example.com's master branch. So +next we explain what a fast-forward is: + +[[fast-forwards]] +Understanding git history: fast-forwards +---------------------------------------- + +In the previous example, when updating an existing branch, "git +fetch" checks to make sure that the most recent commit on the remote +branch is a descendant of the most recent commit on your copy of the +branch before updating your copy of the branch to point at the new +commit. Git calls this process a "fast forward". + +A fast forward looks something like this: + + o--o--o--o <-- old head of the branch + \ + o--o--o <-- new head of the branch + + +In some cases it is possible that the new head will *not* actually be +a descendant of the old head. For example, the developer may have +realized she made a serious mistake, and decided to backtrack, +resulting in a situation like: + + o--o--o--o--a--b <-- old head of the branch + \ + o--o--o <-- new head of the branch + + + +In this case, "git fetch" will fail, and print out a warning. + +In that case, you can still force git to update to the new head, as +described in the following section. However, note that in the +situation above this may mean losing the commits labeled "a" and "b", +unless you've already created a reference of your own pointing to +them. + +Forcing git fetch to do non-fast-forward updates +------------------------------------------------ + +If git fetch fails because the new head of a branch is not a +descendant of the old head, you may force the update with: + +------------------------------------------------- +$ git fetch git://example.com/proj.git +master:refs/remotes/example/master +------------------------------------------------- + +Note the addition of the "+" sign. Be aware that commits which the +old version of example/master pointed at may be lost, as we saw in +the previous section. + +Configuring remote branches +--------------------------- + +We saw above that "origin" is just a shortcut to refer to the +repository which you originally cloned from. This information is +stored in git configuration variables, which you can see using +gitlink:git-repo-config[1]: + +------------------------------------------------- +$ git-repo-config -l +core.repositoryformatversion=0 +core.filemode=true +core.logallrefupdates=true +remote.origin.url=git://git.kernel.org/pub/scm/git/git.git +remote.origin.fetch=+refs/heads/*:refs/remotes/origin/* +branch.master.remote=origin +branch.master.merge=refs/heads/master +------------------------------------------------- + +If there are other repositories that you also use frequently, you can +create similar configuration options to save typing; for example, +after + +------------------------------------------------- +$ git repo-config remote.example.url git://example.com/proj.git +------------------------------------------------- + +then the following two commands will do the same thing: + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:refs/remotes/example/master +$ git fetch example master:refs/remotes/example/master +------------------------------------------------- + +Even better, if you add one more option: + +------------------------------------------------- +$ git repo-config remote.example.fetch master:refs/remotes/example/master +------------------------------------------------- + +then the following commands will all do the same thing: + +------------------------------------------------- +$ git fetch git://example.com/proj.git master:ref/remotes/example/master +$ git fetch example master:ref/remotes/example/master +$ git fetch example example/master +$ git fetch example +------------------------------------------------- + +You can also add a "+" to force the update each time: + +------------------------------------------------- +$ git repo-config remote.example.fetch +master:ref/remotes/example/master +------------------------------------------------- + +Don't do this unless you're sure you won't mind "git fetch" possibly +throwing away commits on mybranch. + +Also note that all of the above configuration can be performed by +directly editing the file .git/config instead of using +gitlink:git-repo-config[1]. + +See gitlink:git-repo-config[1] for more details on the configuration +options mentioned above. Git internals ============= -Architectural overview +There are two object abstractions: the "object database", and the +"current directory cache" aka "index". + +The Object Database +------------------- + +The object database is literally just a content-addressable collection +of objects. All objects are named by their content, which is +approximated by the SHA1 hash of the object itself. Objects may refer +to other objects (by referencing their SHA1 hash), and so you can +build up a hierarchy of objects. + +All objects have a statically determined "type" aka "tag", which is +determined at object creation time, and which identifies the format of +the object (i.e. how it is used, and how it can refer to other +objects). There are currently four different object types: "blob", +"tree", "commit" and "tag". + +A "blob" object cannot refer to any other object, and is, like the type +implies, a pure storage object containing some user data. It is used to +actually store the file data, i.e. a blob object is associated with some +particular version of some file. + +A "tree" object is an object that ties one or more "blob" objects into a +directory structure. In addition, a tree object can refer to other tree +objects, thus creating a directory hierarchy. + +A "commit" object ties such directory hierarchies together into +a DAG of revisions - each "commit" is associated with exactly one tree +(the directory hierarchy at the time of the commit). In addition, a +"commit" refers to one or more "parent" commit objects that describe the +history of how we arrived at that directory hierarchy. + +As a special case, a commit object with no parents is called the "root" +object, and is the point of an initial project commit. Each project +must have at least one root, and while you can tie several different +root objects together into one project by creating a commit object which +has two or more separate roots as its ultimate parents, that's probably +just going to confuse people. So aim for the notion of "one root object +per project", even if git itself does not enforce that. + +A "tag" object symbolically identifies and can be used to sign other +objects. It contains the identifier and type of another object, a +symbolic name (of course!) and, optionally, a signature. + +Regardless of object type, all objects share the following +characteristics: they are all deflated with zlib, and have a header +that not only specifies their type, but also provides size information +about the data in the object. It's worth noting that the SHA1 hash +that is used to name the object is the hash of the original data +plus this header, so `sha1sum` 'file' does not match the object name +for 'file'. +(Historical note: in the dawn of the age of git the hash +was the sha1 of the 'compressed' object.) + +As a result, the general consistency of an object can always be tested +independently of the contents or the type of the object: all objects can +be validated by verifying that (a) their hashes match the content of the +file and (b) the object successfully inflates to a stream of bytes that +forms a sequence of + + + + . + +The structured objects can further have their structure and +connectivity to other objects verified. This is generally done with +the `git-fsck-objects` program, which generates a full dependency graph +of all objects, and verifies their internal consistency (in addition +to just verifying their superficial consistency through the hash). + +The object types in some more detail: + +Blob Object +----------- + +A "blob" object is nothing but a binary blob of data, and doesn't +refer to anything else. There is no signature or any other +verification of the data, so while the object is consistent (it 'is' +indexed by its sha1 hash, so the data itself is certainly correct), it +has absolutely no other attributes. No name associations, no +permissions. It is purely a blob of data (i.e. normally "file +contents"). + +In particular, since the blob is entirely defined by its data, if two +files in a directory tree (or in multiple different versions of the +repository) have the same contents, they will share the same blob +object. The object is totally independent of its location in the +directory tree, and renaming a file does not change the object that +file is associated with in any way. + +A blob is typically created when gitlink:git-update-index[1] +is run, and its data can be accessed by gitlink:git-cat-file[1]. + +Tree Object +----------- + +The next hierarchical object type is the "tree" object. A tree object +is a list of mode/name/blob data, sorted by name. Alternatively, the +mode data may specify a directory mode, in which case instead of +naming a blob, that name is associated with another TREE object. + +Like the "blob" object, a tree object is uniquely determined by the +set contents, and so two separate but identical trees will always +share the exact same object. This is true at all levels, i.e. it's +true for a "leaf" tree (which does not refer to any other trees, only +blobs) as well as for a whole subdirectory. + +For that reason a "tree" object is just a pure data abstraction: it +has no history, no signatures, no verification of validity, except +that since the contents are again protected by the hash itself, we can +trust that the tree is immutable and its contents never change. + +So you can trust the contents of a tree to be valid, the same way you +can trust the contents of a blob, but you don't know where those +contents 'came' from. + +Side note on trees: since a "tree" object is a sorted list of +"filename+content", you can create a diff between two trees without +actually having to unpack two trees. Just ignore all common parts, +and your diff will look right. In other words, you can effectively +(and efficiently) tell the difference between any two random trees by +O(n) where "n" is the size of the difference, rather than the size of +the tree. + +Side note 2 on trees: since the name of a "blob" depends entirely and +exclusively on its contents (i.e. there are no names or permissions +involved), you can see trivial renames or permission changes by +noticing that the blob stayed the same. However, renames with data +changes need a smarter "diff" implementation. + +A tree is created with gitlink:git-write-tree[1] and +its data can be accessed by gitlink:git-ls-tree[1]. +Two trees can be compared with gitlink:git-diff-tree[1]. + +Commit Object +------------- + +The "commit" object is an object that introduces the notion of +history into the picture. In contrast to the other objects, it +doesn't just describe the physical state of a tree, it describes how +we got there, and why. + +A "commit" is defined by the tree-object that it results in, the +parent commits (zero, one or more) that led up to that point, and a +comment on what happened. Again, a commit is not trusted per se: +the contents are well-defined and "safe" due to the cryptographically +strong signatures at all levels, but there is no reason to believe +that the tree is "good" or that the merge information makes sense. +The parents do not have to actually have any relationship with the +result, for example. + +Note on commits: unlike real SCM's, commits do not contain +rename information or file mode change information. All of that is +implicit in the trees involved (the result tree, and the result trees +of the parents), and describing that makes no sense in this idiotic +file manager. + +A commit is created with gitlink:git-commit-tree[1] and +its data can be accessed by gitlink:git-cat-file[1]. + +Trust +----- + +An aside on the notion of "trust". Trust is really outside the scope +of "git", but it's worth noting a few things. First off, since +everything is hashed with SHA1, you 'can' trust that an object is +intact and has not been messed with by external sources. So the name +of an object uniquely identifies a known state - just not a state that +you may want to trust. + +Furthermore, since the SHA1 signature of a commit refers to the +SHA1 signatures of the tree it is associated with and the signatures +of the parent, a single named commit specifies uniquely a whole set +of history, with full contents. You can't later fake any step of the +way once you have the name of a commit. + +So to introduce some real trust in the system, the only thing you need +to do is to digitally sign just 'one' special note, which includes the +name of a top-level commit. Your digital signature shows others +that you trust that commit, and the immutability of the history of +commits tells others that they can trust the whole history. + +In other words, you can easily validate a whole archive by just +sending out a single email that tells the people the name (SHA1 hash) +of the top commit, and digitally sign that email using something +like GPG/PGP. + +To assist in this, git also provides the tag object... + +Tag Object +---------- + +Git provides the "tag" object to simplify creating, managing and +exchanging symbolic and signed tokens. The "tag" object at its +simplest simply symbolically identifies another object by containing +the sha1, type and symbolic name. + +However it can optionally contain additional signature information +(which git doesn't care about as long as there's less than 8k of +it). This can then be verified externally to git. + +Note that despite the tag features, "git" itself only handles content +integrity; the trust framework (and signature provision and +verification) has to come from outside. + +A tag is created with gitlink:git-mktag[1], +its data can be accessed by gitlink:git-cat-file[1], +and the signature can be verified by +gitlink:git-verify-tag[1]. + + +The "index" aka "Current Directory Cache" +----------------------------------------- + +The index is a simple binary file, which contains an efficient +representation of a virtual directory content at some random time. It +does so by a simple array that associates a set of names, dates, +permissions and content (aka "blob") objects together. The cache is +always kept ordered by name, and names are unique (with a few very +specific rules) at any point in time, but the cache has no long-term +meaning, and can be partially updated at any time. + +In particular, the index certainly does not need to be consistent with +the current directory contents (in fact, most operations will depend on +different ways to make the index 'not' be consistent with the directory +hierarchy), but it has three very important attributes: + +'(a) it can re-generate the full state it caches (not just the +directory structure: it contains pointers to the "blob" objects so +that it can regenerate the data too)' + +As a special case, there is a clear and unambiguous one-way mapping +from a current directory cache to a "tree object", which can be +efficiently created from just the current directory cache without +actually looking at any other data. So a directory cache at any one +time uniquely specifies one and only one "tree" object (but has +additional data to make it easy to match up that tree object with what +has happened in the directory) + +'(b) it has efficient methods for finding inconsistencies between that +cached state ("tree object waiting to be instantiated") and the +current state.' + +'(c) it can additionally efficiently represent information about merge +conflicts between different tree objects, allowing each pathname to be +associated with sufficient information about the trees involved that +you can create a three-way merge between them.' + +Those are the three ONLY things that the directory cache does. It's a +cache, and the normal operation is to re-generate it completely from a +known tree object, or update/compare it with a live tree that is being +developed. If you blow the directory cache away entirely, you generally +haven't lost any information as long as you have the name of the tree +that it described. + +At the same time, the index is at the same time also the +staging area for creating new trees, and creating a new tree always +involves a controlled modification of the index file. In particular, +the index file can have the representation of an intermediate tree that +has not yet been instantiated. So the index can be thought of as a +write-back cache, which can contain dirty information that has not yet +been written back to the backing store. + + + +The Workflow +------------ + +Generally, all "git" operations work on the index file. Some operations +work *purely* on the index file (showing the current state of the +index), but most operations move data to and from the index file. Either +from the database or from the working directory. Thus there are four +main combinations: + +working directory -> index +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +You update the index with information from the working directory with +the gitlink:git-update-index[1] command. You +generally update the index information by just specifying the filename +you want to update, like so: + +------------------------------------------------- +$ git-update-index filename +------------------------------------------------- + +but to avoid common mistakes with filename globbing etc, the command +will not normally add totally new entries or remove old entries, +i.e. it will normally just update existing cache entries. + +To tell git that yes, you really do realize that certain files no +longer exist, or that new files should be added, you +should use the `--remove` and `--add` flags respectively. + +NOTE! A `--remove` flag does 'not' mean that subsequent filenames will +necessarily be removed: if the files still exist in your directory +structure, the index will be updated with their new status, not +removed. The only thing `--remove` means is that update-cache will be +considering a removed file to be a valid thing, and if the file really +does not exist any more, it will update the index accordingly. + +As a special case, you can also do `git-update-index --refresh`, which +will refresh the "stat" information of each index to match the current +stat information. It will 'not' update the object status itself, and +it will only update the fields that are used to quickly test whether +an object still matches its old backing store object. + +index -> object database +~~~~~~~~~~~~~~~~~~~~~~~~ + +You write your current index file to a "tree" object with the program + +------------------------------------------------- +$ git-write-tree +------------------------------------------------- + +that doesn't come with any options - it will just write out the +current index into the set of tree objects that describe that state, +and it will return the name of the resulting top-level tree. You can +use that tree to re-generate the index at any time by going in the +other direction: + +object database -> index +~~~~~~~~~~~~~~~~~~~~~~~~ + +You read a "tree" file from the object database, and use that to +populate (and overwrite - don't do this if your index contains any +unsaved state that you might want to restore later!) your current +index. Normal operation is just + +------------------------------------------------- +$ git-read-tree +------------------------------------------------- + +and your index file will now be equivalent to the tree that you saved +earlier. However, that is only your 'index' file: your working +directory contents have not been modified. + +index -> working directory +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +You update your working directory from the index by "checking out" +files. This is not a very common operation, since normally you'd just +keep your files updated, and rather than write to your working +directory, you'd tell the index files about the changes in your +working directory (i.e. `git-update-index`). + +However, if you decide to jump to a new version, or check out somebody +else's version, or just restore a previous tree, you'd populate your +index file with read-tree, and then you need to check out the result +with + +------------------------------------------------- +$ git-checkout-index filename +------------------------------------------------- + +or, if you want to check out all of the index, use `-a`. + +NOTE! git-checkout-index normally refuses to overwrite old files, so +if you have an old version of the tree already checked out, you will +need to use the "-f" flag ('before' the "-a" flag or the filename) to +'force' the checkout. + + +Finally, there are a few odds and ends which are not purely moving +from one representation to the other: + +Tying it all together +~~~~~~~~~~~~~~~~~~~~~ + +To commit a tree you have instantiated with "git-write-tree", you'd +create a "commit" object that refers to that tree and the history +behind it - most notably the "parent" commits that preceded it in +history. + +Normally a "commit" has one parent: the previous state of the tree +before a certain change was made. However, sometimes it can have two +or more parent commits, in which case we call it a "merge", due to the +fact that such a commit brings together ("merges") two or more +previous states represented by other commits. + +In other words, while a "tree" represents a particular directory state +of a working directory, a "commit" represents that state in "time", +and explains how we got there. + +You create a commit object by giving it the tree that describes the +state at the time of the commit, and a list of parents: + +------------------------------------------------- +$ git-commit-tree -p [-p ..] +------------------------------------------------- + +and then giving the reason for the commit on stdin (either through +redirection from a pipe or file, or by just typing it at the tty). + +git-commit-tree will return the name of the object that represents +that commit, and you should save it away for later use. Normally, +you'd commit a new `HEAD` state, and while git doesn't care where you +save the note about that state, in practice we tend to just write the +result to the file pointed at by `.git/HEAD`, so that we can always see +what the last committed state was. + +Here is an ASCII art by Jon Loeliger that illustrates how +various pieces fit together. + +------------ + + commit-tree + commit obj + +----+ + | | + | | + V V + +-----------+ + | Object DB | + | Backing | + | Store | + +-----------+ + ^ + write-tree | | + tree obj | | + | | read-tree + | | tree obj + V + +-----------+ + | Index | + | "cache" | + +-----------+ + update-index ^ + blob obj | | + | | + checkout-index -u | | checkout-index + stat | | blob obj + V + +-----------+ + | Working | + | Directory | + +-----------+ + +------------ + + +Examining the data +------------------ + +You can examine the data represented in the object database and the +index with various helper tools. For every object, you can use +gitlink:git-cat-file[1] to examine details about the +object: + +------------------------------------------------- +$ git-cat-file -t +------------------------------------------------- + +shows the type of the object, and once you have the type (which is +usually implicit in where you find the object), you can use + +------------------------------------------------- +$ git-cat-file blob|tree|commit|tag +------------------------------------------------- + +to show its contents. NOTE! Trees have binary content, and as a result +there is a special helper for showing that content, called +`git-ls-tree`, which turns the binary content into a more easily +readable form. + +It's especially instructive to look at "commit" objects, since those +tend to be small and fairly self-explanatory. In particular, if you +follow the convention of having the top commit name in `.git/HEAD`, +you can do + +------------------------------------------------- +$ git-cat-file commit HEAD +------------------------------------------------- + +to see what the top commit was. + +Merging multiple trees ---------------------- -TODO: Sources, README, core-tutorial, tutorial-2.txt, technical/ +Git helps you do a three-way merge, which you can expand to n-way by +repeating the merge procedure arbitrary times until you finally +"commit" the state. The normal situation is that you'd only do one +three-way merge (two parents), and commit it, but if you like to, you +can do multiple parents in one go. + +To do a three-way merge, you need the two sets of "commit" objects +that you want to merge, use those to find the closest common parent (a +third "commit" object), and then use those commit objects to find the +state of the directory ("tree" object) at these points. + +To get the "base" for the merge, you first look up the common parent +of two commits with + +------------------------------------------------- +$ git-merge-base +------------------------------------------------- + +which will return you the commit they are both based on. You should +now look up the "tree" objects of those commits, which you can easily +do with (for example) + +------------------------------------------------- +$ git-cat-file commit | head -1 +------------------------------------------------- + +since the tree object information is always the first line in a commit +object. + +Once you know the three trees you are going to merge (the one +"original" tree, aka the common case, and the two "result" trees, aka +the branches you want to merge), you do a "merge" read into the +index. This will complain if it has to throw away your old index contents, so you should +make sure that you've committed those - in fact you would normally +always do a merge against your last commit (which should thus match +what you have in your current index anyway). + +To do the merge, do + +------------------------------------------------- +$ git-read-tree -m -u +------------------------------------------------- + +which will do all trivial merge operations for you directly in the +index file, and you can just write the result out with +`git-write-tree`. + + +Merging multiple trees, continued +--------------------------------- + +Sadly, many merges aren't trivial. If there are files that have +been added.moved or removed, or if both branches have modified the +same file, you will be left with an index tree that contains "merge +entries" in it. Such an index tree can 'NOT' be written out to a tree +object, and you will have to resolve any such merge clashes using +other tools before you can write out the result. + +You can examine such index state with `git-ls-files --unmerged` +command. An example: + +------------------------------------------------ +$ git-read-tree -m $orig HEAD $target +$ git-ls-files --unmerged +100644 263414f423d0e4d70dae8fe53fa34614ff3e2860 1 hello.c +100644 06fa6a24256dc7e560efa5687fa84b51f0263c3a 2 hello.c +100644 cc44c73eb783565da5831b4d820c962954019b69 3 hello.c +------------------------------------------------ + +Each line of the `git-ls-files --unmerged` output begins with +the blob mode bits, blob SHA1, 'stage number', and the +filename. The 'stage number' is git's way to say which tree it +came from: stage 1 corresponds to `$orig` tree, stage 2 `HEAD` +tree, and stage3 `$target` tree. + +Earlier we said that trivial merges are done inside +`git-read-tree -m`. For example, if the file did not change +from `$orig` to `HEAD` nor `$target`, or if the file changed +from `$orig` to `HEAD` and `$orig` to `$target` the same way, +obviously the final outcome is what is in `HEAD`. What the +above example shows is that file `hello.c` was changed from +`$orig` to `HEAD` and `$orig` to `$target` in a different way. +You could resolve this by running your favorite 3-way merge +program, e.g. `diff3` or `merge`, on the blob objects from +these three stages yourself, like this: + +------------------------------------------------ +$ git-cat-file blob 263414f... >hello.c~1 +$ git-cat-file blob 06fa6a2... >hello.c~2 +$ git-cat-file blob cc44c73... >hello.c~3 +$ merge hello.c~2 hello.c~1 hello.c~3 +------------------------------------------------ + +This would leave the merge result in `hello.c~2` file, along +with conflict markers if there are conflicts. After verifying +the merge result makes sense, you can tell git what the final +merge result for this file is by: + +------------------------------------------------- +$ mv -f hello.c~2 hello.c +$ git-update-index hello.c +------------------------------------------------- + +When a path is in unmerged state, running `git-update-index` for +that path tells git to mark the path resolved. + +The above is the description of a git merge at the lowest level, +to help you understand what conceptually happens under the hood. +In practice, nobody, not even git itself, uses three `git-cat-file` +for this. There is `git-merge-index` program that extracts the +stages to temporary files and calls a "merge" script on it: + +------------------------------------------------- +$ git-merge-index git-merge-one-file hello.c +------------------------------------------------- + +and that is what higher level `git resolve` is implemented with. + +How git stores objects efficiently: pack files +---------------------------------------------- + +We've seen how git stores each object in a file named after the +object's SHA1 hash. + +Unfortunately this system becomes inefficient once a project has a +lot of objects. Try this on an old project: + +------------------------------------------------ +$ git count-objects +6930 objects, 47620 kilobytes +------------------------------------------------ + +The first number is the number of objects which are kept in +individual files. The second is the amount of space taken up by +those "loose" objects. + +You can save space and make git faster by moving these loose objects in +to a "pack file", which stores a group of objects in an efficient +compressed format; the details of how pack files are formatted can be +found in link:technical/pack-format.txt[technical/pack-format.txt]. + +To put the loose objects into a pack, just run git repack: + +------------------------------------------------ +$ git repack +Generating pack... +Done counting 6020 objects. +Deltifying 6020 objects. + 100% (6020/6020) done +Writing 6020 objects. + 100% (6020/6020) done +Total 6020, written 6020 (delta 4070), reused 0 (delta 0) +Pack pack-3e54ad29d5b2e05838c75df582c65257b8d08e1c created. +------------------------------------------------ + +You can then run + +------------------------------------------------ +$ git prune +------------------------------------------------ + +to remove any of the "loose" objects that are now contained in the +pack. This will also remove any unreferenced objects (which may be +created when, for example, you use "git reset" to remove a commit). +You can verify that the loose objects are gone by looking at the +.git/objects directory or by running + +------------------------------------------------ +$ git count-objects +0 objects, 0 kilobytes +------------------------------------------------ + +Although the object files are gone, any commands that refer to those +objects will work exactly as they did before. + +The gitlink:git-gc[1] command performs packing, pruning, and more for +you, so is normally the only high-level command you need. Glossary of git terms ===================== @@ -1976,15 +2731,12 @@ Scan man pages to see if any assume more background than this manual provides. Simplify beginning by suggesting disconnected head instead of -temporary branch creation. +temporary branch creation? Explain how to refer to file stages in the "how to resolve a merge" section: diff -1, -2, -3, --ours, --theirs :1:/path notation. The "git ls-files --unmerged --stage" thing is sorta useful too, -actually. And note gitk --merge. Also what's easiest way to see -common merge base? Note also text where I claim rebase and am -conflicts are resolved like merges isn't generally true, at least by -default--fix. +actually. And note gitk --merge. Add more good examples. Entire sections of just cookbook examples might be a good idea; maybe make an "advanced examples" section a @@ -1992,8 +2744,6 @@ standard end-of-chapter section? Include cross-references to the glossary, where appropriate. -Add quickstart as first chapter. - To document: reflogs, git reflog expire shallow clones?? See draft 1.5.0 release notes for some documentation. -- cgit v0.10.2-6-g49f6 From 21dcb3b7abfb9e06914a36d1afbc768de6db5f1f Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 28 Jan 2007 23:29:19 -0500 Subject: user-manual: git-fsck, dangling objects Initial import of fsck and dangling objects discussion, mostly lifted from an email from Linus. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 87c605f..ee551ea 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1373,12 +1373,37 @@ Ensuring reliability Checking the repository for corruption ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -TODO: - git-fsck - "dangling objects" explanation - Brief explanation here, - include forward reference to longer explanation from - Linus, to be added to later chapter +The gitlink:git-fsck-objects[1] command runs a number of self-consistency +checks on the repository, and reports on any problems. This may take some +time. The most common warning by far is about "dangling" objects: + +------------------------------------------------- +$ git fsck-objects +dangling commit 7281251ddd2a61e38657c827739c57015671a6b3 +dangling commit 2706a059f258c6b245f298dc4ff2ccd30ec21a63 +dangling commit 13472b7c4b80851a1bc551779171dcb03655e9b5 +dangling blob 218761f9d90712d37a9c5e36f406f92202db07eb +dangling commit bf093535a34a4d35731aa2bd90fe6b176302f14f +dangling commit 8e4bec7f2ddaa268bef999853c25755452100f8e +dangling tree d50bb86186bf27b681d25af89d3b5b68382e4085 +dangling tree b24c2473f1fd3d91352a624795be026d64c8841f +... +------------------------------------------------- + +Dangling objects are objects that are harmless, but also unnecessary; you can +remove them at any time with gitlink:git-prune[1] or the --prune option to +gitlink:git-gc[1]: + +------------------------------------------------- +$ git gc --prune +------------------------------------------------- + +This may be time-consuming. Unlike most other git operations (including git-gc +when run without any options), it is not safe to prune while other git +operations are in progress in the same repository. + +For more about dangling merges, see <>. + Recovering lost changes ~~~~~~~~~~~~~~~~~~~~~~~ @@ -2693,6 +2718,93 @@ objects will work exactly as they did before. The gitlink:git-gc[1] command performs packing, pruning, and more for you, so is normally the only high-level command you need. +[[dangling-objects]] +Dangling objects +^^^^^^^^^^^^^^^^ + +The gitlink:git-fsck-objects[1] command will sometimes complain about dangling +objects. They are not a problem. + +The most common cause of dangling objects is that you've rebased a branch, or +you have pulled from somebody else who rebased a branch--see +<>. In that case, the old head of the original branch +still exists, as does obviously everything it pointed to. The branch pointer +itself just doesn't, since you replaced it with another one. + +There are also other situations too that cause dangling objects. For example, a +"dangling blob" may arise because you did a "git add" of a file, but then, +before you actually committed it and made it part of the bigger picture, you +changed something else in that file and committed that *updated* thing - the +old state that you added originally ends up not being pointed to by any +commit or tree, so it's now a dangling blob object. + +Similarly, when the "recursive" merge strategy runs, and finds that there +are criss-cross merges and thus more than one merge base (which is fairly +unusual, but it does happen), it will generate one temporary midway tree +(or possibly even more, if you had lots of criss-crossing merges and +more than two merge bases) as a temporary internal merge base, and again, +those are real objects, but the end result will not end up pointing to +them, so they end up "dangling" in your repository. + +Generally, dangling objects aren't anything to worry about. They can even +be very useful: if you screw something up, the dangling objects can be how +you recover your old tree (say, you did a rebase, and realized that you +really didn't want to - you can look at what dangling objects you have, +and decide to reset your head to some old dangling state). + +For commits, the most useful thing to do with dangling objects tends to be +to do a simple + +------------------------------------------------ +$ gitk --not --all +------------------------------------------------ + +which means exactly what it sounds like: it says that you want to see the +commit history that is described by the dangling commit(s), but you do NOT +want to see the history that is described by all your branches and tags +(which are the things you normally reach). That basically shows you in a +nice way what the dangling commit was (and notice that it might not be +just one commit: we only report the "tip of the line" as being dangling, +but there might be a whole deep and complex commit history that has gotten +dropped - rebasing will do that). + +For blobs and trees, you can't do the same, but you can examine them. You +can just do + +------------------------------------------------ +$ git show +------------------------------------------------ + +to show what the contents of the blob were (or, for a tree, basically what +the "ls" for that directory was), and that may give you some idea of what +the operation was that left that dangling object. + +Usually, dangling blobs and trees aren't very interesting. They're almost +always the result of either being a half-way mergebase (the blob will +often even have the conflict markers from a merge in it, if you have had +conflicting merges that you fixed up by hand), or simply because you +interrupted a "git fetch" with ^C or something like that, leaving _some_ +of the new objects in the object database, but just dangling and useless. + +Anyway, once you are sure that you're not interested in any dangling +state, you can just prune all unreachable objects: + +------------------------------------------------ +$ git prune +------------------------------------------------ + +and they'll be gone. But you should only run "git prune" on a quiescent +repository - it's kind of like doing a filesystem fsck recovery: you don't +want to do that while the filesystem is mounted. + +(The same is true of "git-fsck-objects" itself, btw - but since +git-fsck-objects never actually *changes* the repository, it just reports +on what it found, git-fsck-objects itself is never "dangerous" to run. +Running it while somebody is actually changing the repository can cause +confusing and scary messages, but it won't actually do anything bad. In +contrast, running "git prune" while somebody is actively changing the +repository is a *BAD* idea). + Glossary of git terms ===================== -- cgit v0.10.2-6-g49f6 From 04e50e94570cc2e71abe0451723fbd89e4893c5f Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 28 Jan 2007 23:31:47 -0500 Subject: user-manual: fsck-objects -> fsck There seems to be an agreement to rename fsck-objects to fsck. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index ee551ea..663fe9b 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -238,7 +238,7 @@ Repository maintenance Check for corruption: ----------------------------------------------- -$ git fsck-objects +$ git fsck ----------------------------------------------- Recompress, remove unused cruft: @@ -1373,12 +1373,12 @@ Ensuring reliability Checking the repository for corruption ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The gitlink:git-fsck-objects[1] command runs a number of self-consistency +The gitlink:git-fsck[1] command runs a number of self-consistency checks on the repository, and reports on any problems. This may take some time. The most common warning by far is about "dangling" objects: ------------------------------------------------- -$ git fsck-objects +$ git fsck dangling commit 7281251ddd2a61e38657c827739c57015671a6b3 dangling commit 2706a059f258c6b245f298dc4ff2ccd30ec21a63 dangling commit 13472b7c4b80851a1bc551779171dcb03655e9b5 @@ -2126,7 +2126,7 @@ size> + + . The structured objects can further have their structure and connectivity to other objects verified. This is generally done with -the `git-fsck-objects` program, which generates a full dependency graph +the `git-fsck` program, which generates a full dependency graph of all objects, and verifies their internal consistency (in addition to just verifying their superficial consistency through the hash). @@ -2722,7 +2722,7 @@ you, so is normally the only high-level command you need. Dangling objects ^^^^^^^^^^^^^^^^ -The gitlink:git-fsck-objects[1] command will sometimes complain about dangling +The gitlink:git-fsck[1] command will sometimes complain about dangling objects. They are not a problem. The most common cause of dangling objects is that you've rebased a branch, or @@ -2797,9 +2797,9 @@ and they'll be gone. But you should only run "git prune" on a quiescent repository - it's kind of like doing a filesystem fsck recovery: you don't want to do that while the filesystem is mounted. -(The same is true of "git-fsck-objects" itself, btw - but since -git-fsck-objects never actually *changes* the repository, it just reports -on what it found, git-fsck-objects itself is never "dangerous" to run. +(The same is true of "git-fsck" itself, btw - but since +git-fsck never actually *changes* the repository, it just reports +on what it found, git-fsck itself is never "dangerous" to run. Running it while somebody is actually changing the repository can cause confusing and scary messages, but it won't actually do anything bad. In contrast, running "git prune" while somebody is actively changing the -- cgit v0.10.2-6-g49f6 From 9d13bda3fffc948c0b2576f08a33ac7f547fe9b3 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Sun, 28 Jan 2007 23:50:22 -0500 Subject: user-manual: repo-config -> config Looks like we're going to allow git-config as the preferred alias to git-repo-config, so let's document that instead. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 663fe9b..3e367a0 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1450,7 +1450,7 @@ $ git pull ------------------------------------------------- See the descriptions of the branch..remote and -branch..merge options in gitlink:git-repo-config[1] to learn +branch..merge options in gitlink:git-config[1] to learn how to control these defaults depending on the current branch. In addition to saving you keystrokes, "git pull" also helps you by @@ -1685,7 +1685,7 @@ $ git push public-repo master ------------------------------------------------- See the explanations of the remote..url, branch..remote, -and remote..push options in gitlink:git-repo-config[1] for +and remote..push options in gitlink:git-config[1] for details. Setting up a shared repository @@ -1999,10 +1999,10 @@ Configuring remote branches We saw above that "origin" is just a shortcut to refer to the repository which you originally cloned from. This information is stored in git configuration variables, which you can see using -gitlink:git-repo-config[1]: +gitlink:git-config[1]: ------------------------------------------------- -$ git-repo-config -l +$ git config -l core.repositoryformatversion=0 core.filemode=true core.logallrefupdates=true @@ -2017,7 +2017,7 @@ create similar configuration options to save typing; for example, after ------------------------------------------------- -$ git repo-config remote.example.url git://example.com/proj.git +$ git config remote.example.url git://example.com/proj.git ------------------------------------------------- then the following two commands will do the same thing: @@ -2030,7 +2030,7 @@ $ git fetch example master:refs/remotes/example/master Even better, if you add one more option: ------------------------------------------------- -$ git repo-config remote.example.fetch master:refs/remotes/example/master +$ git config remote.example.fetch master:refs/remotes/example/master ------------------------------------------------- then the following commands will all do the same thing: @@ -2045,7 +2045,7 @@ $ git fetch example You can also add a "+" to force the update each time: ------------------------------------------------- -$ git repo-config remote.example.fetch +master:ref/remotes/example/master +$ git config remote.example.fetch +master:ref/remotes/example/master ------------------------------------------------- Don't do this unless you're sure you won't mind "git fetch" possibly @@ -2053,9 +2053,9 @@ throwing away commits on mybranch. Also note that all of the above configuration can be performed by directly editing the file .git/config instead of using -gitlink:git-repo-config[1]. +gitlink:git-config[1]. -See gitlink:git-repo-config[1] for more details on the configuration +See gitlink:git-config[1] for more details on the configuration options mentioned above. -- cgit v0.10.2-6-g49f6 From fc90c536dc5f29a89402e5f5411a3283c644b864 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 00:17:51 -0500 Subject: user-manual: add references to git-config man page Direct editing of config files may be more natural for users than using the git-config commandline; but we should still reference the git-config man page when we describe such editing, so people know where to go for details on the config file syntax and meanings of the variables. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 3e367a0..ce0e91b 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -601,9 +601,10 @@ $ cat .git/config ... ------------------------------------------------- -This is what causes git to track the remote's branches; you may -modify or delete these configuration options by editing .git/config -with a text editor. +This is what causes git to track the remote's branches; you may modify +or delete these configuration options by editing .git/config with a +text editor. (See the "CONFIGURATION FILE" section of +gitlink:git-config[1] for details.) Exploring git history ===================== @@ -955,6 +956,9 @@ $ cat >~/.gitconfig <<\EOF EOF ------------------------------------------------ +(See the "CONFIGURATION FILE" section of gitlink:git-config[1] for +details on the configuration file.) + Creating a new repository ------------------------- -- cgit v0.10.2-6-g49f6 From 988b27d3f5ca06e0ae8fd48acaf90f33cfac4304 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 00:33:57 -0500 Subject: user-manual: typo fix Oops Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index ce0e91b..1eab4ac 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1406,7 +1406,7 @@ This may be time-consuming. Unlike most other git operations (including git-gc when run without any options), it is not safe to prune while other git operations are in progress in the same repository. -For more about dangling merges, see <>. +For more about dangling objects, see <>. Recovering lost changes -- cgit v0.10.2-6-g49f6 From 61b41790c4d6abccf86c87f7ae312da8adbac3dd Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 00:45:33 -0500 Subject: user-manual: fix a header level Oops. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 1eab4ac..11497b7 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -2724,7 +2724,7 @@ you, so is normally the only high-level command you need. [[dangling-objects]] Dangling objects -^^^^^^^^^^^^^^^^ +---------------- The gitlink:git-fsck[1] command will sometimes complain about dangling objects. They are not a problem. -- cgit v0.10.2-6-g49f6 From 559e4d7a0d2e98e887ac93c78631d3eeef378716 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 01:31:35 -0500 Subject: user-manual: reflogs, other recovery Add a brief discussion of reflogs. Also recovery of dangling commits seems to fit in here, so move some of the discussion out of Linus's email to here. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 11497b7..be5a1f4 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1412,10 +1412,82 @@ For more about dangling objects, see <>. Recovering lost changes ~~~~~~~~~~~~~~~~~~~~~~~ -TODO: - reflog - git-fsck - low-level examination of objects +Reflogs +^^^^^^^ + +Say you modify a branch with gitlink:git-reset[1] --hard, and then +realize that the branch was the only reference you had to that point in +history. + +Fortunately, git also keeps a log, called a "reflog", of all the +previous values of each branch. So in this case you can still find the +old history using, for example, + +------------------------------------------------- +$ git log master@{1} +------------------------------------------------- + +This lists the commits reachable from the previous version of the head. +This syntax can be used to with any git command that accepts a commit, +not just with git log. Some other examples: + +------------------------------------------------- +$ git show master@{2} # See where the branch pointed 2, +$ git show master@{3} # 3, ... changes ago. +$ gitk master@{yesterday} # See where it pointed yesterday, +$ gitk master@{"1 week ago"} # ... or last week +------------------------------------------------- + +The reflogs are kept by default for 30 days, after which they may be +pruned. See gitlink:git-reflink[1] and gitlink:git-gc[1] to learn +how to control this pruning, and see the "SPECIFYING REVISIONS" +section of gitlink:git-rev-parse[1] for details. + +Note that the reflog history is very different from normal git history. +While normal history is shared by every repository that works on the +same project, the reflog history is not shared: it tells you only about +how the branches in your local repository have changed over time. + +Examining dangling objects +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +In some situations the reflog may not be able to save you. For +example, suppose you delete a branch, then realize you need the history +it pointed you. The reflog is also deleted; however, if you have not +yet pruned the repository, then you may still be able to find +the lost commits; run git-fsck and watch for output that mentions +"dangling commits": + +------------------------------------------------- +$ git fsck +dangling commit 7281251ddd2a61e38657c827739c57015671a6b3 +dangling commit 2706a059f258c6b245f298dc4ff2ccd30ec21a63 +dangling commit 13472b7c4b80851a1bc551779171dcb03655e9b5 +... +------------------------------------------------- + +and watch for output that mentions "dangling commits". You can examine +one of those dangling commits with, for example, + +------------------------------------------------ +$ gitk 7281251ddd --not --all +------------------------------------------------ + +which does what it sounds like: it says that you want to see the commit +history that is described by the dangling commit(s), but not the +history that is described by all your existing branches and tags. Thus +you get exactly the history reachable from that commit that is lost. +(And notice that it might not be just one commit: we only report the +"tip of the line" as being dangling, but there might be a whole deep +and complex commit history that was gotten dropped.) + +If you decide you want the history back, you can always create a new +reference pointing to it, for example, a new branch: + +------------------------------------------------ +$ git branch recovered-branch 7281251ddd +------------------------------------------------ + Sharing development with others =============================== @@ -2756,22 +2828,13 @@ you recover your old tree (say, you did a rebase, and realized that you really didn't want to - you can look at what dangling objects you have, and decide to reset your head to some old dangling state). -For commits, the most useful thing to do with dangling objects tends to be -to do a simple +For commits, the most useful thing to do with dangling objects tends to +be to do a simple ------------------------------------------------ $ gitk --not --all ------------------------------------------------ -which means exactly what it sounds like: it says that you want to see the -commit history that is described by the dangling commit(s), but you do NOT -want to see the history that is described by all your branches and tags -(which are the things you normally reach). That basically shows you in a -nice way what the dangling commit was (and notice that it might not be -just one commit: we only report the "tip of the line" as being dangling, -but there might be a whole deep and complex commit history that has gotten -dropped - rebasing will do that). - For blobs and trees, you can't do the same, but you can examine them. You can just do -- cgit v0.10.2-6-g49f6 From 1191ee1824aca8f817e531db6b779a11e7fe3c28 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 01:33:55 -0500 Subject: user-manual: rewrap a few long lines Rewrap some long lines. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index be5a1f4..8fd38e4 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1377,8 +1377,8 @@ Ensuring reliability Checking the repository for corruption ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -The gitlink:git-fsck[1] command runs a number of self-consistency -checks on the repository, and reports on any problems. This may take some +The gitlink:git-fsck[1] command runs a number of self-consistency checks +on the repository, and reports on any problems. This may take some time. The most common warning by far is about "dangling" objects: ------------------------------------------------- @@ -1394,17 +1394,17 @@ dangling tree b24c2473f1fd3d91352a624795be026d64c8841f ... ------------------------------------------------- -Dangling objects are objects that are harmless, but also unnecessary; you can -remove them at any time with gitlink:git-prune[1] or the --prune option to -gitlink:git-gc[1]: +Dangling objects are objects that are harmless, but also unnecessary; +you can remove them at any time with gitlink:git-prune[1] or the --prune +option to gitlink:git-gc[1]: ------------------------------------------------- $ git gc --prune ------------------------------------------------- -This may be time-consuming. Unlike most other git operations (including git-gc -when run without any options), it is not safe to prune while other git -operations are in progress in the same repository. +This may be time-consuming. Unlike most other git operations (including +git-gc when run without any options), it is not safe to prune while +other git operations are in progress in the same repository. For more about dangling objects, see <>. @@ -1537,8 +1537,8 @@ repository that you pulled from. <>; instead, your branch will just be updated to point to the latest commit from the upstream branch). -The git-pull command can also be given "." as the "remote" repository, in -which case it just merges in a branch from the current repository; so +The git-pull command can also be given "." as the "remote" repository, +in which case it just merges in a branch from the current repository; so the commands ------------------------------------------------- @@ -2645,13 +2645,13 @@ $ git-cat-file commit | head -1 since the tree object information is always the first line in a commit object. -Once you know the three trees you are going to merge (the one -"original" tree, aka the common case, and the two "result" trees, aka -the branches you want to merge), you do a "merge" read into the -index. This will complain if it has to throw away your old index contents, so you should +Once you know the three trees you are going to merge (the one "original" +tree, aka the common case, and the two "result" trees, aka the branches +you want to merge), you do a "merge" read into the index. This will +complain if it has to throw away your old index contents, so you should make sure that you've committed those - in fact you would normally -always do a merge against your last commit (which should thus match -what you have in your current index anyway). +always do a merge against your last commit (which should thus match what +you have in your current index anyway). To do the merge, do @@ -2801,32 +2801,34 @@ Dangling objects The gitlink:git-fsck[1] command will sometimes complain about dangling objects. They are not a problem. -The most common cause of dangling objects is that you've rebased a branch, or -you have pulled from somebody else who rebased a branch--see -<>. In that case, the old head of the original branch -still exists, as does obviously everything it pointed to. The branch pointer -itself just doesn't, since you replaced it with another one. - -There are also other situations too that cause dangling objects. For example, a -"dangling blob" may arise because you did a "git add" of a file, but then, -before you actually committed it and made it part of the bigger picture, you -changed something else in that file and committed that *updated* thing - the -old state that you added originally ends up not being pointed to by any -commit or tree, so it's now a dangling blob object. - -Similarly, when the "recursive" merge strategy runs, and finds that there -are criss-cross merges and thus more than one merge base (which is fairly -unusual, but it does happen), it will generate one temporary midway tree -(or possibly even more, if you had lots of criss-crossing merges and -more than two merge bases) as a temporary internal merge base, and again, -those are real objects, but the end result will not end up pointing to -them, so they end up "dangling" in your repository. - -Generally, dangling objects aren't anything to worry about. They can even -be very useful: if you screw something up, the dangling objects can be how -you recover your old tree (say, you did a rebase, and realized that you -really didn't want to - you can look at what dangling objects you have, -and decide to reset your head to some old dangling state). +The most common cause of dangling objects is that you've rebased a +branch, or you have pulled from somebody else who rebased a branch--see +<>. In that case, the old head of the original +branch still exists, as does obviously everything it pointed to. The +branch pointer itself just doesn't, since you replaced it with another +one. + +There are also other situations too that cause dangling objects. For +example, a "dangling blob" may arise because you did a "git add" of a +file, but then, before you actually committed it and made it part of the +bigger picture, you changed something else in that file and committed +that *updated* thing - the old state that you added originally ends up +not being pointed to by any commit or tree, so it's now a dangling blob +object. + +Similarly, when the "recursive" merge strategy runs, and finds that +there are criss-cross merges and thus more than one merge base (which is +fairly unusual, but it does happen), it will generate one temporary +midway tree (or possibly even more, if you had lots of criss-crossing +merges and more than two merge bases) as a temporary internal merge +base, and again, those are real objects, but the end result will not end +up pointing to them, so they end up "dangling" in your repository. + +Generally, dangling objects aren't anything to worry about. They can +even be very useful: if you screw something up, the dangling objects can +be how you recover your old tree (say, you did a rebase, and realized +that you really didn't want to - you can look at what dangling objects +you have, and decide to reset your head to some old dangling state). For commits, the most useful thing to do with dangling objects tends to be to do a simple @@ -2835,23 +2837,24 @@ be to do a simple $ gitk --not --all ------------------------------------------------ -For blobs and trees, you can't do the same, but you can examine them. You -can just do +For blobs and trees, you can't do the same, but you can examine them. +You can just do ------------------------------------------------ $ git show ------------------------------------------------ -to show what the contents of the blob were (or, for a tree, basically what -the "ls" for that directory was), and that may give you some idea of what -the operation was that left that dangling object. +to show what the contents of the blob were (or, for a tree, basically +what the "ls" for that directory was), and that may give you some idea +of what the operation was that left that dangling object. -Usually, dangling blobs and trees aren't very interesting. They're almost -always the result of either being a half-way mergebase (the blob will -often even have the conflict markers from a merge in it, if you have had -conflicting merges that you fixed up by hand), or simply because you -interrupted a "git fetch" with ^C or something like that, leaving _some_ -of the new objects in the object database, but just dangling and useless. +Usually, dangling blobs and trees aren't very interesting. They're +almost always the result of either being a half-way mergebase (the blob +will often even have the conflict markers from a merge in it, if you +have had conflicting merges that you fixed up by hand), or simply +because you interrupted a "git fetch" with ^C or something like that, +leaving _some_ of the new objects in the object database, but just +dangling and useless. Anyway, once you are sure that you're not interested in any dangling state, you can just prune all unreachable objects: @@ -2860,9 +2863,9 @@ state, you can just prune all unreachable objects: $ git prune ------------------------------------------------ -and they'll be gone. But you should only run "git prune" on a quiescent -repository - it's kind of like doing a filesystem fsck recovery: you don't -want to do that while the filesystem is mounted. +and they'll be gone. But you should only run "git prune" on a quiescent +repository - it's kind of like doing a filesystem fsck recovery: you +don't want to do that while the filesystem is mounted. (The same is true of "git-fsck" itself, btw - but since git-fsck never actually *changes* the repository, it just reports -- cgit v0.10.2-6-g49f6 From 9a241220fd19c93a89501bfef51ce4ec79a79033 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 01:43:33 -0500 Subject: user-manual: minor "TODO" updates I still really want a section on interoperability with CVS, subversion, etc., but I'm not getting around to it very fast, so just add this to the TODO section for now. And a few other minor todo updates. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 8fd38e4..b4980a2 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1784,11 +1784,6 @@ Examples TODO: topic branches, typical roles as in everyday.txt, ? -Working with other version control systems -========================================== - -TODO: CVS, Subversion, series-of-release-tarballs, etc. - [[cleaning-up-history]] Rewriting history and maintaining patch series ============================================== @@ -2902,7 +2897,6 @@ everything in between. Scan Documentation/ for other stuff left out; in particular: howto's - README some of technical/? hooks etc. @@ -2926,6 +2920,9 @@ standard end-of-chapter section? Include cross-references to the glossary, where appropriate. -To document: - reflogs, git reflog expire - shallow clones?? See draft 1.5.0 release notes for some documentation. +Document shallow clones? See draft 1.5.0 release notes for some +documentation. + +Add a sectin on working with other version control systems, including +CVS, Subversion, and just imports of series of release tarballs. + -- cgit v0.10.2-6-g49f6 From 4a7979ca829530c4e5661d553449b0b073a50db3 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 01:55:33 -0500 Subject: user-manual: document git-show-branch example Document Junio's show-branch trick for finding out which tags are descendents of a given comit. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index b4980a2..5f41a2d 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -933,12 +933,38 @@ actually is an ancestor of v1.5.0-rc1. Alternatively, note that ------------------------------------------------- -$ git log v1.5.0-rc1..305db0fd +$ git log v1.5.0-rc1..e05db0fd ------------------------------------------------- -will produce empty output if and only if v1.5.0-rc1 includes 305db0fd, +will produce empty output if and only if v1.5.0-rc1 includes e05db0fd, because it outputs only commits that are not reachable from v1.5.0-rc1. +As yet another alternative, the gitlink:git-show-branch[1] command lists +the commits reachable from its arguments with a display on the left-hand +side that indicates which arguments that commit is reachable from. So, +you can run something like + +------------------------------------------------- +$ git show-branch e05db0fd v1.5.0-rc0 v1.5.0-rc1 v1.5.0-rc2 +! [e05db0fd] Fix warnings in sha1_file.c - use C99 printf format if +available + ! [v1.5.0-rc0] GIT v1.5.0 preview + ! [v1.5.0-rc1] GIT v1.5.0-rc1 + ! [v1.5.0-rc2] GIT v1.5.0-rc2 +... +------------------------------------------------- + +then search for a line that looks like + +------------------------------------------------- ++ ++ [e05db0fd] Fix warnings in sha1_file.c - use C99 printf format if +available +------------------------------------------------- + +Which shows that e05db0fd is reachable from itself, from v1.5.0-rc1, and +from v1.5.0-rc2, but not from v1.5.0-rc0. + + Developing with git =================== -- cgit v0.10.2-6-g49f6 From d55ae921ce33dc989b6b77317f25a5aa58d406fe Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Mon, 29 Jan 2007 02:16:45 -0500 Subject: user-manual: SHA1 -> object name Prefer "object name" to SHA1, at least in higher level documentation. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 5f41a2d..61c8b43 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -692,7 +692,7 @@ Naming commits We have seen several ways of naming commits already: - - 40-hexdigit SHA1 id + - 40-hexdigit object name - branch name: refers to the commit at the head of the given branch - tag name: refers to the commit pointed to by the given tag @@ -705,7 +705,7 @@ gitlink:git-rev-parse[1] man page for the complete list of ways to name revisions. Some examples: ------------------------------------------------- -$ git show fb47ddb2 # the first few characters of the SHA1 id +$ git show fb47ddb2 # the first few characters of the object name # are usually enough to specify it uniquely $ git show HEAD^ # the parent of the HEAD commit $ git show HEAD^^ # the grandparent @@ -743,8 +743,8 @@ which refers to the other branch that we're merging in to the current branch. The gitlink:git-rev-parse[1] command is a low-level command that is -occasionally useful for translating some name for a commit to the SHA1 id for -that commit: +occasionally useful for translating some name for a commit to the object +name for that commit: ------------------------------------------------- $ git rev-parse origin @@ -861,7 +861,7 @@ $ git diff origin..master will tell you whether the contents of the project are the same at the two branches; in theory, however, it's possible that the same project contents could have been arrived at by two different historical -routes. You could compare the SHA1 id's: +routes. You could compare the object names: ------------------------------------------------- $ git rev-list origin -- cgit v0.10.2-6-g49f6 From 036be17e0a6fe38beed3a163a4a944b5ed3d7b7b Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Sun, 28 Jan 2007 23:16:46 -0800 Subject: Two small typofixes. Signed-off-by: Junio C Hamano diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 61c8b43..9b32819 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1465,7 +1465,7 @@ $ gitk master@{"1 week ago"} # ... or last week ------------------------------------------------- The reflogs are kept by default for 30 days, after which they may be -pruned. See gitlink:git-reflink[1] and gitlink:git-gc[1] to learn +pruned. See gitlink:git-reflog[1] and gitlink:git-gc[1] to learn how to control this pruning, and see the "SPECIFYING REVISIONS" section of gitlink:git-rev-parse[1] for details. @@ -1580,7 +1580,7 @@ Submitting patches to a project If you just have a few changes, the simplest way to submit them may just be to send them as patches in email: -First, use gitlink:git-format-patches[1]; for example: +First, use gitlink:git-format-patch[1]; for example: ------------------------------------------------- $ git format-patch origin -- cgit v0.10.2-6-g49f6 From a8cd1402f039d5e130a32a32a56fd29fbd46c1e8 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 30 Jan 2007 12:43:36 -0500 Subject: user-manual: point to README for gitweb information I'd like complete gitweb setup instructions some day, but for now just refer to the gitweb README. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index 9b32819..c6d1451 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1802,7 +1802,9 @@ set this up. Allow web browsing of a repository ---------------------------------- -TODO: Brief setup-instructions for gitweb +The gitweb cgi script provides users an easy way to browse your +project's files and history without having to install git; see the file +gitweb/README in the git source tree for instructions on setting it up. Examples -------- @@ -2952,3 +2954,4 @@ documentation. Add a sectin on working with other version control systems, including CVS, Subversion, and just imports of series of release tarballs. +More details on gitweb? -- cgit v0.10.2-6-g49f6 From 0b375ab0a511568fe2c80aede9a297b640212d35 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 30 Jan 2007 12:48:48 -0500 Subject: user-manual: todo's Update todo's. Signed-off-by: "J. Bruce Fields" diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index c6d1451..b6916d1 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -2927,7 +2927,7 @@ Scan Documentation/ for other stuff left out; in particular: howto's some of technical/? hooks - etc. + list of commands in gitlink:git[1] Scan email archives for other stuff left out @@ -2955,3 +2955,5 @@ Add a sectin on working with other version control systems, including CVS, Subversion, and just imports of series of release tarballs. More details on gitweb? + +Write a chapter on using plumbing and writing scripts. -- cgit v0.10.2-6-g49f6