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authorJunio C Hamano <junkio@cox.net>2007-05-07 21:46:48 (GMT)
committerJunio C Hamano <junkio@cox.net>2007-05-07 21:46:48 (GMT)
commit679c7c56ed9f73db5892fe17ef9b67b84b0ca242 (patch)
tree971c66f5b641bb5f2aeca09acb5ad48afc9064fb /Documentation/user-manual.txt
parente701ccc3883959b4ba5fada7a903e8e9eaddcba7 (diff)
parent53a58245863eff3d70aaa3ac75d7d57e843fc91d (diff)
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Merge branch 'maint'
* maint: Documentation: don't reference non-existent 'git-cvsapplycommit' user-manual: stop deprecating the manual user-manual: miscellaneous editing user-manual: fix .gitconfig editing examples user-manual: clean up fast-forward and dangling-objects sections user-manual: add section ID's user-manual: more discussion of detached heads, fix typos git-gui: Allow spaces in path to 'wish' gitk: Allow user to choose whether to see the diff, old file, or new file
Diffstat (limited to 'Documentation/user-manual.txt')
-rw-r--r--Documentation/user-manual.txt258
1 files changed, 183 insertions, 75 deletions
diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index dff438f..67f5b9b 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -23,12 +23,14 @@ pages. For a command such as "git clone", just use
$ man git-clone
------------------------------------------------
+[[git-quick-start]]
Git Quick Start
===============
This is a quick summary of the major commands; the following chapters
will explain how these work in more detail.
+[[quick-creating-a-new-repository]]
Creating a new repository
-------------------------
@@ -50,11 +52,12 @@ $ git clone git://example.com/pub/project.git
$ cd project
-----------------------------------------------
+[[managing-branches]]
Managing branches
-----------------
-----------------------------------------------
-$ git branch # list all branches in this repo
+$ git branch # list all local 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"
@@ -112,6 +115,7 @@ $ git branch -r # list all remote branches
-----------------------------------------------
+[[exploring-history]]
Exploring history
-----------------
@@ -147,13 +151,14 @@ $ git bisect bad # if this revision is bad.
# repeat until done.
-----------------------------------------------
+[[making-changes]]
Making changes
--------------
Make sure git knows who to blame:
------------------------------------------------
-$ cat >~/.gitconfig <<\EOF
+$ cat >>~/.gitconfig <<\EOF
[user]
name = Your Name Comes Here
email = you@yourdomain.example.com
@@ -177,6 +182,7 @@ $ git commit d.txt # use latest content only of d.txt
$ git commit -a # use latest content of all tracked files
-----------------------------------------------
+[[merging]]
Merging
-------
@@ -187,6 +193,7 @@ $ git pull git://example.com/project.git master
$ git pull . test # equivalent to git merge test
-----------------------------------------------
+[[sharing-your-changes]]
Sharing your changes
--------------------
@@ -232,6 +239,7 @@ $ git remote add example ssh://example.com/project.git
$ git push example test
-----------------------------------------------
+[[repository-maintenance]]
Repository maintenance
----------------------
@@ -247,9 +255,11 @@ Recompress, remove unused cruft:
$ git gc
-----------------------------------------------
+[[repositories-and-branches]]
Repositories and Branches
=========================
+[[how-to-get-a-git-repository]]
How to get a git repository
---------------------------
@@ -280,6 +290,7 @@ contains all the information about the history of the project.
In most of the following, examples will be taken from one of the two
repositories above.
+[[how-to-check-out]]
How to check out a different version of a project
-------------------------------------------------
@@ -352,6 +363,7 @@ 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-commits]]
Understanding History: Commits
------------------------------
@@ -407,6 +419,7 @@ In fact, in <<git-internals>> we shall see that everything stored in git
history, including file data and directory contents, is stored in an object
with a name that is a hash of its contents.
+[[understanding-reachability]]
Understanding history: commits, parents, and reachability
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -431,6 +444,7 @@ 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.
+[[history-diagrams]]
Understanding history: History diagrams
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -450,6 +464,7 @@ lines drawn with - / and \. Time goes left to right:
If we need to talk about a particular commit, the character "o" may
be replaced with another letter or number.
+[[what-is-a-branch]]
Understanding history: What is a branch?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -463,6 +478,7 @@ the line of three commits leading up to that point as all being part of
However, when no confusion will result, we often just use the term
"branch" both for branches and for branch heads.
+[[manipulating-branches]]
Manipulating branches
---------------------
@@ -480,8 +496,8 @@ git branch <branch> <start-point>::
including using a branch name or a tag name
git branch -d <branch>::
delete the branch <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.
+ points to a commit which is not reachable from the current
+ branch, this command will fail with a warning.
git branch -D <branch>::
even if the branch points to a commit not reachable
from the current branch, you may know that that commit
@@ -527,18 +543,18 @@ and git branch shows that you are no longer on a branch:
------------------------------------------------
$ cat .git/HEAD
427abfa28afedffadfca9dd8b067eb6d36bac53f
-git branch
+$ git branch
* (no branch)
master
------------------------------------------------
In this case we say that the HEAD is "detached".
-This can be an easy way to check out a particular version without having
-to make up a name for a new branch. However, keep in mind that when you
-switch away from the (for example, by checking out something else), you
-can lose track of what the HEAD used to point to.
+This is an easy way to check out a particular version without having to
+make up a name for the new branch. You can still create a new branch
+(or tag) for this version later if you decide to.
+[[examining-remote-branches]]
Examining branches from a remote repository
-------------------------------------------
@@ -586,13 +602,9 @@ shorthand:
The full name is occasionally useful if, for example, there ever
exists a tag and a branch with the same name.
-As another useful shortcut, if the repository "origin" posesses only
-a single branch, you can refer to that branch as just "origin".
-
-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.
+As another useful shortcut, the "HEAD" of a repository can be referred
+to just using the name of that repository. So, for example, "origin"
+is usually a shortcut for the HEAD branch in the repository "origin".
For the complete list of paths which git checks for references, and
the order it uses to decide which to choose when there are multiple
@@ -612,6 +624,7 @@ 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]]
Fetching branches from other repositories
-----------------------------------------
@@ -654,6 +667,7 @@ 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]]
Exploring git history
=====================
@@ -668,6 +682,7 @@ history of a project.
We start with one specialized tool that is useful for finding the
commit that introduced a bug into a project.
+[[using-bisect]]
How to use bisect to find a regression
--------------------------------------
@@ -735,6 +750,7 @@ $ git reset --hard fb47ddb2db...
then test, run "bisect good" or "bisect bad" as appropriate, and
continue.
+[[naming-commits]]
Naming commits
--------------
@@ -799,6 +815,7 @@ $ git rev-parse origin
e05db0fd4f31dde7005f075a84f96b360d05984b
-------------------------------------------------
+[[creating-tags]]
Creating tags
-------------
@@ -811,11 +828,12 @@ $ 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.
+This creates a "lightweight" tag. If you would also like to include a
+comment with the tag, and possibly sign it cryptographically, then you
+should create a tag object instead; see the gitlink:git-tag[1] man page
+for details.
+[[browsing-revisions]]
Browsing revisions
------------------
@@ -857,6 +875,7 @@ backwards through the parents; however, since git history can contain
multiple independent lines of development, the particular order that
commits are listed in may be somewhat arbitrary.
+[[generating-diffs]]
Generating diffs
----------------
@@ -878,6 +897,7 @@ 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]]
Viewing old file versions
-------------------------
@@ -893,9 +913,11 @@ $ 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.
+[[history-examples]]
Examples
--------
+[[checking-for-equal-branches]]
Check whether two branches point at the same history
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -928,6 +950,7 @@ $ git log origin...master
will return no commits when the two branches are equal.
+[[finding-tagged-descendants]]
Find first tagged version including a given fix
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1013,27 +1036,29 @@ 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]]
Developing with git
===================
+[[telling-git-your-name]]
Telling git your name
---------------------
Before creating any commits, you should introduce yourself to git. The
-easiest way to do so is:
+easiest way to do so is to make sure the following lines appear in a
+file named .gitconfig in your home directory:
------------------------------------------------
-$ cat >~/.gitconfig <<\EOF
[user]
name = Your Name Comes Here
email = you@yourdomain.example.com
-EOF
------------------------------------------------
(See the "CONFIGURATION FILE" section of gitlink:git-config[1] for
details on the configuration file.)
+[[creating-a-new-repository]]
Creating a new repository
-------------------------
@@ -1147,9 +1172,12 @@ $ git diff --cached # difference between HEAD and the index; what
$ git diff # difference between the index file and your
# working directory; changes that would not
# be included if you ran "commit" now.
+$ git diff HEAD # difference between HEAD and working tree; what
+ # would be committed if you ran "commit -a" now.
$ git status # a brief per-file summary of the above.
-------------------------------------------------
+[[creating-good-commit-messages]]
Creating good commit messages
-----------------------------
@@ -1160,6 +1188,7 @@ 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]]
How to merge
------------
@@ -1192,8 +1221,6 @@ 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
-----------------
@@ -1237,6 +1264,7 @@ your own if desired.
The above is all you need to know to resolve a simple merge. But git
also provides more information to help resolve conflicts:
+[[conflict-resolution]]
Getting conflict-resolution help during a merge
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1329,6 +1357,9 @@ $ gitk --merge
These will display all commits which exist only on HEAD or on
MERGE_HEAD, and which touch an unmerged file.
+You may also use gitlink:git-mergetool, which lets you merge the
+unmerged files using external tools such as emacs or kdiff3.
+
Each time you resolve the conflicts in a file and update the index:
-------------------------------------------------
@@ -1360,6 +1391,7 @@ 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-forwards]]
Fast-forward merges
-------------------
@@ -1368,13 +1400,13 @@ 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
-<<fast-forwards,fast forward>>; 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.
+However, if the current branch is a descendant of the other--so every
+commit present in the one is already contained in the other--then git
+just performs a "fast forward"; 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.
+[[fixing-mistakes]]
Fixing mistakes
---------------
@@ -1399,6 +1431,7 @@ fundamentally different ways to fix the problem:
change, and cannot correctly perform repeated merges from
a branch that has had its history changed.
+[[reverting-a-commit]]
Fixing a mistake with a new commit
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1453,6 +1486,7 @@ It is also possible to edit commits further back in the history, but
this is an advanced topic to be left for
<<cleaning-up-history,another chapter>>.
+[[checkout-of-path]]
Checking out an old version of a file
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1479,6 +1513,7 @@ $ git show HEAD^:path/to/file
which will display the given version of the file.
+[[ensuring-good-performance]]
Ensuring good performance
-------------------------
@@ -1495,9 +1530,12 @@ $ 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]]
Ensuring reliability
--------------------
+[[checking-for-corruption]]
Checking the repository for corruption
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1518,8 +1556,10 @@ 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
+Dangling objects are not a problem. At worst they may take up a little
+extra disk space. They can sometimes provide a last-resort method of
+recovery lost work--see <<dangling-objects>> for details. However, if
+you want, you may remove them with gitlink:git-prune[1] or the --prune
option to gitlink:git-gc[1]:
-------------------------------------------------
@@ -1530,12 +1570,11 @@ 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 <<dangling-objects>>.
-
-
+[[recovering-lost-changes]]
Recovering lost changes
~~~~~~~~~~~~~~~~~~~~~~~
+[[reflogs]]
Reflogs
^^^^^^^
@@ -1560,8 +1599,19 @@ $ 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
+$ git log --walk-reflogs master # show reflog entries for master
-------------------------------------------------
+A separate reflog is kept for the HEAD, so
+
+-------------------------------------------------
+$ git show HEAD@{"1 week ago"}
+-------------------------------------------------
+
+will show what HEAD pointed to one week ago, not what the current branch
+pointed to one week ago. This allows you to see the history of what
+you've checked out.
+
The reflogs are kept by default for 30 days, after which they may be
pruned. See gitlink:git-reflog[1] and gitlink:git-gc[1] to learn
how to control this pruning, and see the "SPECIFYING REVISIONS"
@@ -1572,15 +1622,16 @@ 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.
+[[dangling-object-recovery]]
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 contained. 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":
+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
+contained. 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 in the dangling objects that git-fsck reports. See
+<<dangling-objects>> for the details.
-------------------------------------------------
$ git fsck
@@ -1612,7 +1663,11 @@ reference pointing to it, for example, a new branch:
$ git branch recovered-branch 7281251ddd
------------------------------------------------
+Other types of dangling objects (blobs and trees) are also possible, and
+dangling objects can arise in other situations.
+
+[[sharing-development]]
Sharing development with others
===============================
@@ -1649,9 +1704,16 @@ so often you can accomplish the above with just
$ git pull
-------------------------------------------------
-See the descriptions of the branch.<name>.remote and
-branch.<name>.merge options in gitlink:git-config[1] to learn
-how to control these defaults depending on the current branch.
+See the descriptions of the branch.<name>.remote and branch.<name>.merge
+options in gitlink:git-config[1] to learn how to control these defaults
+depending on the current branch. Also note that the --track option to
+gitlink:git-branch[1] and gitlink:git-checkout[1] can be used to
+automatically set the default remote branch to pull from at the time
+that a branch is created:
+
+-------------------------------------------------
+$ git checkout --track -b origin/maint maint
+-------------------------------------------------
In addition to saving you keystrokes, "git pull" also helps you by
producing a default commit message documenting the branch and
@@ -1672,6 +1734,7 @@ $ git merge branch
are roughly equivalent. The former is actually very commonly used.
+[[submitting-patches]]
Submitting patches to a project
-------------------------------
@@ -1693,6 +1756,7 @@ 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]]
Importing patches to a project
------------------------------
@@ -1772,14 +1836,14 @@ 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
+$ git clone --bare proj.git
-------------------------------------------------
-The resulting directory proj-clone.git will contains a "bare" git
+The resulting directory proj.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
+Next, copy proj.git to the server where you plan to host the
public repository. You can use scp, rsync, or whatever is most
convenient.
@@ -1805,7 +1869,7 @@ 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
+$ git --bare update-server-info
$ chmod a+x hooks/post-update
-------------------------------------------------
@@ -1872,7 +1936,7 @@ As with git-fetch, you may also set up configuration options to
save typing; so, for example, after
-------------------------------------------------
-$ cat >.git/config <<EOF
+$ cat >>.git/config <<EOF
[remote "public-repo"]
url = ssh://yourserver.com/~you/proj.git
EOF
@@ -1888,6 +1952,7 @@ See the explanations of the remote.<name>.url, branch.<name>.remote,
and remote.<name>.push options in gitlink:git-config[1] for
details.
+[[setting-up-a-shared-repository]]
Setting up a shared repository
------------------------------
@@ -1897,6 +1962,7 @@ 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.
+[[setting-up-gitweb]]
Allow web browsing of a repository
----------------------------------
@@ -1904,6 +1970,7 @@ 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/INSTALL in the git source tree for instructions on setting it up.
+[[sharing-development-examples]]
Examples
--------
@@ -1921,6 +1988,7 @@ 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.
+[[patch-series]]
Creating the perfect patch series
---------------------------------
@@ -1953,6 +2021,7 @@ 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.
+[[using-git-rebase]]
Keeping a patch series up to date using git-rebase
--------------------------------------------------
@@ -2034,6 +2103,7 @@ return mywork to the state it had before you started the rebase:
$ git rebase --abort
-------------------------------------------------
+[[modifying-one-commit]]
Modifying a single commit
-------------------------
@@ -2079,6 +2149,7 @@ Note that the immutable nature of git history means that you haven't really
"modified" existing commits; instead, you have replaced the old commits with
new commits having new object names.
+[[reordering-patch-series]]
Reordering or selecting from a patch series
-------------------------------------------
@@ -2108,6 +2179,7 @@ $ git reset --hard origin
Then modify, reorder, or eliminate patches as preferred before applying
them again with gitlink:git-am[1].
+[[patch-series-tools]]
Other tools
-----------
@@ -2115,6 +2187,7 @@ There are numerous other tools, such as stgit, which exist for the
purpose of maintaining a patch series. These are outside of the scope of
this manual.
+[[problems-with-rewriting-history]]
Problems with rewriting history
-------------------------------
@@ -2163,9 +2236,11 @@ branches into their own work.
For true distributed development that supports proper merging,
published branches should never be rewritten.
+[[advanced-branch-management]]
Advanced branch management
==========================
+[[fetching-individual-branches]]
Fetching individual branches
----------------------------
@@ -2191,18 +2266,18 @@ $ 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,fast-forward>> to the commit given by example.com's
+master branch. In more detail:
-[[fast-forwards]]
-Understanding git history: fast-forwards
-----------------------------------------
+[[fetch-fast-forwards]]
+git fetch and 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".
+commit. Git calls this process a <<fast-forwards,fast forward>>.
A fast forward looks something like this:
@@ -2232,6 +2307,7 @@ 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-fetch]]
Forcing git fetch to do non-fast-forward updates
------------------------------------------------
@@ -2242,10 +2318,17 @@ 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 that the
-old version of example/master pointed at may be lost, as we saw in
-the previous section.
+Note the addition of the "+" sign. Alternatively, you can use the "-f"
+flag to force updates of all the fetched branches, as in:
+
+-------------------------------------------------
+$ git fetch -f origin
+-------------------------------------------------
+
+Be aware that commits that the old version of example/master pointed at
+may be lost, as we saw in the previous section.
+[[remote-branch-configuration]]
Configuring remote branches
---------------------------
@@ -2319,6 +2402,7 @@ Git internals
Git depends on two fundamental abstractions: the "object database", and
the "current directory cache" aka "index".
+[[the-object-database]]
The Object Database
-------------------
@@ -2328,7 +2412,7 @@ 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
+All objects have a statically determined "type" 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",
@@ -2351,7 +2435,7 @@ the time of the commit). In addition, a "commit" refers to one or more
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
+commit, 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
@@ -2388,6 +2472,7 @@ to just verifying their superficial consistency through the hash).
The object types in some more detail:
+[[blob-object]]
Blob Object
-----------
@@ -2409,6 +2494,7 @@ 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]]
Tree Object
-----------
@@ -2450,6 +2536,7 @@ 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]]
Commit Object
-------------
@@ -2467,7 +2554,7 @@ 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
+Note on commits: unlike some 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
@@ -2476,6 +2563,7 @@ 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]]
Trust
-----
@@ -2505,6 +2593,7 @@ like GPG/PGP.
To assist in this, git also provides the tag object...
+[[tag-object]]
Tag Object
----------
@@ -2527,11 +2616,12 @@ and the signature can be verified by
gitlink:git-verify-tag[1].
+[[the-index]]
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
+representation of the contents of a virtual directory. 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
@@ -2581,6 +2671,7 @@ been written back to the backing store.
+[[the-workflow]]
The Workflow
------------
@@ -2590,6 +2681,7 @@ 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-to-index]]
working directory -> index
~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2623,6 +2715,7 @@ 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-to-object-database]]
index -> object database
~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2638,6 +2731,7 @@ 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-to-index]]
object database -> index
~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2654,6 +2748,7 @@ 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-to-working-directory]]
index -> working directory
~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2683,6 +2778,7 @@ need to use the "-f" flag ('before' the "-a" flag or the filename) to
Finally, there are a few odds and ends which are not purely moving
from one representation to the other:
+[[tying-it-all-together]]
Tying it all together
~~~~~~~~~~~~~~~~~~~~~
@@ -2758,6 +2854,7 @@ various pieces fit together.
------------
+[[examining-the-data]]
Examining the data
------------------
@@ -2793,6 +2890,7 @@ $ git-cat-file commit HEAD
to see what the top commit was.
+[[merging-multiple-trees]]
Merging multiple trees
----------------------
@@ -2826,7 +2924,7 @@ 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
+tree, aka the common tree, 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
@@ -2844,6 +2942,7 @@ index file, and you can just write the result out with
`git-write-tree`.
+[[merging-multiple-trees-2]]
Merging multiple trees, continued
---------------------------------
@@ -2879,14 +2978,14 @@ 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:
+program, e.g. `diff3`, `merge`, or git's own merge-file, 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
+$ git merge-file hello.c~2 hello.c~1 hello.c~3
------------------------------------------------
This would leave the merge result in `hello.c~2` file, along
@@ -2914,6 +3013,7 @@ $ git-merge-index git-merge-one-file hello.c
and that is what higher level `git merge -s resolve` is implemented with.
+[[pack-files]]
How git stores objects efficiently: pack files
----------------------------------------------
@@ -2984,11 +3084,10 @@ 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
<<cleaning-up-history>>. 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.
+branch still exists, as does 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
+There are also other situations 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
@@ -3010,15 +3109,22 @@ 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
+For commits, you can just use:
------------------------------------------------
$ gitk <dangling-commit-sha-goes-here> --not --all
------------------------------------------------
-For blobs and trees, you can't do the same, but you can examine them.
-You can just do
+This asks for all the history reachable from the given commit but not
+from any branch, tag, or other reference. If you decide it's something
+you want, you can always create a new reference to it, e.g.,
+
+------------------------------------------------
+$ git branch recovered-branch <dangling-commit-sha-goes-here>
+------------------------------------------------
+
+For blobs and trees, you can't do the same, but you can still examine
+them. You can just do
------------------------------------------------
$ git show <dangling-blob/tree-sha-goes-here>
@@ -3055,8 +3161,10 @@ 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]]
include::glossary.txt[]
+[[todo]]
Notes and todo list for this manual
===================================