Hooks used by git ================= Hooks are little scripts you can place in `$GIT_DIR/hooks` directory to trigger action at certain points. When `git-init` is run, a handful example hooks are copied in the `hooks` directory of the new repository, but by default they are all disabled. To enable a hook, make it executable with `chmod +x`. This document describes the currently defined hooks. applypatch-msg -------------- This hook is invoked by `git-applypatch` script, which is typically invoked by `git-applymbox`. It takes a single parameter, the name of the file that holds the proposed commit log message. Exiting with non-zero status causes `git-applypatch` to abort before applying the patch. The hook is allowed to edit the message file in place, and can be used to normalize the message into some project standard format (if the project has one). It can also be used to refuse the commit after inspecting the message file. The default 'applypatch-msg' hook, when enabled, runs the 'commit-msg' hook, if the latter is enabled. pre-applypatch -------------- This hook is invoked by `git-applypatch` script, which is typically invoked by `git-applymbox`. It takes no parameter, and is invoked after the patch is applied, but before a commit is made. Exiting with non-zero status causes the working tree after application of the patch not committed. It can be used to inspect the current working tree and refuse to make a commit if it does not pass certain test. The default 'pre-applypatch' hook, when enabled, runs the 'pre-commit' hook, if the latter is enabled. post-applypatch --------------- This hook is invoked by `git-applypatch` script, which is typically invoked by `git-applymbox`. It takes no parameter, and is invoked after the patch is applied and a commit is made. This hook is meant primarily for notification, and cannot affect the outcome of `git-applypatch`. pre-commit ---------- This hook is invoked by `git-commit`, and can be bypassed with `\--no-verify` option. It takes no parameter, and is invoked before obtaining the proposed commit log message and making a commit. Exiting with non-zero status from this script causes the `git-commit` to abort. The default 'pre-commit' hook, when enabled, catches introduction of lines with trailing whitespaces and aborts the commit when such a line is found. commit-msg ---------- This hook is invoked by `git-commit`, and can be bypassed with `\--no-verify` option. It takes a single parameter, the name of the file that holds the proposed commit log message. Exiting with non-zero status causes the `git-commit` to abort. The hook is allowed to edit the message file in place, and can be used to normalize the message into some project standard format (if the project has one). It can also be used to refuse the commit after inspecting the message file. The default 'commit-msg' hook, when enabled, detects duplicate "Signed-off-by" lines, and aborts the commit if one is found. post-commit ----------- This hook is invoked by `git-commit`. It takes no parameter, and is invoked after a commit is made. This hook is meant primarily for notification, and cannot affect the outcome of `git-commit`. [[pre-receive]] pre-receive ----------- This hook is invoked by `git-receive-pack` on the remote repository, which happens when a `git push` is done on a local repository. Just before starting to update refs on the remote repository, the pre-receive hook is invoked. Its exit status determines the success or failure of the update. This hook executes once for the receive operation. It takes no arguments, but for each ref to be updated it receives on standard input a line of the format: SP SP LF where `` is the old object name stored in the ref, `` is the new object name to be stored in the ref and `` is the full name of the ref. When creating a new ref, `` is 40 `0`. If the hook exits with non-zero status, none of the refs will be updated. If the hook exits with zero, updating of individual refs can still be prevented by the <> hook. If you want to report something to the `git-send-pack` on the other end, you can simply `echo` your messages. [[update]] update ------ This hook is invoked by `git-receive-pack` on the remote repository, which happens when a `git push` is done on a local repository. Just before updating the ref on the remote repository, the update hook is invoked. Its exit status determines the success or failure of the ref update. The hook executes once for each ref to be updated, and takes three parameters: - the name of the ref being updated, - the old object name stored in the ref, - and the new objectname to be stored in the ref. A zero exit from the update hook allows the ref to be updated. Exiting with a non-zero status prevents `git-receive-pack` from updating that ref. This hook can be used to prevent 'forced' update on certain refs by making sure that the object name is a commit object that is a descendant of the commit object named by the old object name. That is, to enforce a "fast forward only" policy. It could also be used to log the old..new status. However, it does not know the entire set of branches, so it would end up firing one e-mail per ref when used naively, though. The <> hook is more suited to that. Another use suggested on the mailing list is to use this hook to implement access control which is finer grained than the one based on filesystem group. The standard output of this hook is sent to `stderr`, so if you want to report something to the `git-send-pack` on the other end, you can simply `echo` your messages. The default 'update' hook, when enabled--and with `hooks.allowunannotated` config option turned on--prevents unannotated tags to be pushed. [[post-receive]] post-receive ------------ This hook is invoked by `git-receive-pack` on the remote repository, which happens when a `git push` is done on a local repository. It executes on the remote repository once after all the refs have been updated. This hook executes once for the receive operation. It takes no arguments, but gets the same information as the `pre-receive` hook does on its standard input. This hook does not affect the outcome of `git-receive-pack`, as it is called after the real work is done. This supersedes the [[post-update]] hook in that it actually get's both old and new values of all the refs. If you want to report something to the `git-send-pack` on the other end, you can simply `echo` your messages. The default 'post-receive' hook is empty, but there is a sample script `post-receive-email` provided in the `contrib/hooks` directory in git distribution, which implements sending commit emails. [[post-update]] post-update ----------- This hook is invoked by `git-receive-pack` on the remote repository, which happens when a `git push` is done on a local repository. It executes on the remote repository once after all the refs have been updated. It takes a variable number of parameters, each of which is the name of ref that was actually updated. This hook is meant primarily for notification, and cannot affect the outcome of `git-receive-pack`. The 'post-update' hook can tell what are the heads that were pushed, but it does not know what their original and updated values are, so it is a poor place to do log old..new. In general, `post-receive` hook is preferred when the hook needs to decide its acion on the status of the entire set of refs being updated, as this hook is called once per ref, with information only on a single ref at a time. When enabled, the default 'post-update' hook runs `git-update-server-info` to keep the information used by dumb transports (e.g., HTTP) up-to-date. If you are publishing a git repository that is accessible via HTTP, you should probably enable this hook. Both standard output and standard error output are forwarded to `git-send-pack` on the other end.