GITHOOKS(5) Git Manual GITHOOKS(5)
NAME
githooks - Hooks used by Git
SYNOPSIS
$GIT_DIR/hooks/*
DESCRIPTION
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 of example hooks are copied into the hooks directory of the new repository, but by
default they are all disabled. To enable a hook, rename it by removing its .sample suffix.
Note
It is also a requirement for a given hook to be executable. However - in a freshly initialized repository
- the .sample files are executable by default.
This document describes the currently defined hooks.
HOOKS
applypatch-msg
This hook is invoked by git am script. It takes a single parameter, the name of the file that holds the
proposed commit log message. Exiting with non-zero status causes git am 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 am. It takes no parameter, and is invoked after the patch is applied, but before a
commit is made.
If it exits with non-zero status, then the working tree will not be committed after applying the patch.
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 am. 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 am.
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.
All the git commit hooks are invoked with the environment variable GIT_EDITOR=: if the command will not bring
up an editor to modify the commit message.
The purpose of the hook is to edit the message file in place, and it is not suppressed by the --no-verify
option. A non-zero exit means a failure of the hook and aborts the commit. It should not be used as
replacement for pre-commit hook.
The sample prepare-commit-msg hook that comes with Git comments out the Conflicts: part of a merge’s commit
message.
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-rebase
This hook is called by git rebase and can be used to prevent a branch from getting rebased. The hook may be
called with one or two parameters. The first parameter is the upstream from which the series was forked. The
second parameter is the branch being rebased, and is not set when rebasing the current branch.
post-checkout
This hook is invoked when a git checkout is run after having updated the worktree. The hook is given three
parameters: the ref of the previous HEAD, the ref of the new HEAD (which may or may not have changed), and a
flag indicating whether the checkout was a branch checkout (changing branches, flag=1) or a file checkout
(retrieving a file from the index, flag=0). This hook cannot affect the outcome of git checkout.
It is also run after git clone, unless the --no-checkout (-n) option is used. The first parameter given to the
hook is the null-ref, the second the ref of the new HEAD and the flag is always 1.
This hook can be used to perform repository validity checks, auto-display differences from the previous HEAD
if different, or set working dir metadata properties.
post-merge
This hook is invoked by git merge, which happens when a git pull is done on a local repository. The hook takes
a single parameter, a status flag specifying whether or not the merge being done was a squash merge. This hook
cannot affect the outcome of git merge and is not executed, if the merge failed due to conflicts.
This hook can be used in conjunction with a corresponding pre-commit hook to save and restore any form of
metadata associated with the working tree (eg: permissions/ownership, ACLS, etc). See
contrib/hooks/setgitperms.perl for an example of how to do this.
pre-push
This hook is called by git push and can be used to prevent a push from taking place. The hook is called with
two parameters which provide the name and location of the destination remote, if a named remote is not being
used both values will be the same.
SHA-1> will be 40 0. If the local commit was specified by something other than a name which could be expanded
(such as HEAD~, or a SHA-1) it will be supplied as it was originally given.
If this hook exits with a non-zero status, git push will abort without pushing anything. Information about why
the push is rejected may be sent to the user by writing to standard error.
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:
<old-value> SP <new-value> SP <ref-name> LF
where <old-value> is the old object name stored in the ref, <new-value> is the new object name to be stored in
the ref and <ref-name> is the full name of the ref. When creating a new ref, <old-value> 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 update hook.
Both standard output and standard error output are forwarded to git send-pack on the other end, so you can
simply echo messages for the user.
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 post-receive 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.
Both standard output and standard error output are forwarded to git send-pack on the other end, so you can
simply echo messages for the user.
This supersedes the post-update hook in that it gets both old and new values of all the refs in addition to
their names.
Both standard output and standard error output are forwarded to git send-pack on the other end, so you can
simply echo messages for the user.
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
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. The post-receive hook does get both original
and updated values of the refs. You might consider it instead if you need them.
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, so you can
simply echo messages for the user.
pre-auto-gc
This hook is invoked by git gc --auto. It takes no parameter, and exiting with non-zero status from this
script causes the git gc --auto to abort.
post-rewrite
This hook is invoked by commands that rewrite commits (git commit --amend, git-rebase; currently
git-filter-branch does not call it!). Its first argument denotes the command it was invoked by: currently one
of amend or rebase. Further command-dependent arguments may be passed in the future.
The hook receives a list of the rewritten commits on stdin, in the format
<old-sha1> SP <new-sha1> [ SP <extra-info> ] LF
The extra-info is again command-dependent. If it is empty, the preceding SP is also omitted. Currently, no
commands pass any extra-info.
The hook always runs after the automatic note copying (see "notes.rewrite.<command>" in git-config.txt(1)) has
happened, and thus has access to these notes.
The following command-specific comments apply:
rebase
For the squash and fixup operation, all commits that were squashed are listed as being rewritten to the
squashed commit. This means that there will be several lines sharing the same new-sha1.
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