NAME

       githooks - Hooks used by Git

SYNOPSIS

       $GIT_DIR/hooks/* (or `git config core.hooksPath`/*)

DESCRIPTION

       Hooks are programs you can place in a hooks directory to trigger actions at certain points in git’s
       execution. Hooks that don’t have the executable bit set are ignored.

       By default the hooks directory is $GIT_DIR/hooks, but that can be changed via the core.hooksPath
       configuration variable (see git-config(1)).

       Before Git invokes a hook, it changes its working directory to either $GIT_DIR in a bare repository or
       the root of the working tree in a non-bare repository. An exception are hooks triggered during a push
       (pre-receive, update, post-receive, post-update, push-to-checkout) which are always executed in $GIT_DIR.

       Hooks can get their arguments via the environment, command-line arguments, and stdin. See the
       documentation for each hook below for details.

       git init may copy hooks to the new repository, depending on its configuration. See the "TEMPLATE
       DIRECTORY" section in git-init(1) for details. When the rest of this document refers to "default hooks"
       it’s talking about the default template shipped with Git.

       The currently supported hooks are described below.

HOOKS

   applypatch-msg
       This hook is invoked by git am. It takes a single parameter, the name of the file that holds the proposed
       commit log message. Exiting with a 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. 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 the --no-verify option. It takes no
       parameters, and is invoked before obtaining the proposed commit log message and making a commit. Exiting
       with a non-zero status from this script causes the git commit command to abort before creating a commit.

       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.

   prepare-commit-msg
       This hook is invoked by git commit right after preparing the default log message, and before the editor
       is started.

       It takes one to three parameters. The first is the name of the file that contains the commit log message.
       The second is the source of the commit message, and can be: message (if a -m or -F option was given);
       template (if a -t option was given or the configuration option commit.template is set); merge (if the
       commit is a merge or a .git/MERGE_MSG file exists); squash (if a .git/SQUASH_MSG file exists); or commit,
       followed by a commit SHA-1 (if a -c, -C or --amend option was given).

       If the exit status is non-zero, git commit will abort.

       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 removes the help message found in the commented
       portion of the commit template.

   commit-msg
       This hook is invoked by git commit and git merge, and can be bypassed with the --no-verify option. It
       takes a single parameter, the name of the file that holds the proposed commit log message. Exiting with a
       non-zero status causes the command 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. 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 parameters, 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. Likewise for
       git worktree add unless --no-checkout is used.

       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 (e.g.: 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.

       Information about what is to be pushed is provided on the hook’s standard input with lines of the form:

           <local ref> SP <local sha1> SP <remote ref> SP <remote sha1> LF

       For instance, if the command git push origin master:foreign were run the hook would receive a line like
       the following:

           refs/heads/master 67890 refs/heads/foreign 12345

       although the full, 40-character SHA-1s would be supplied. If the foreign ref does not yet exist the
       <remote SHA-1> will be 40 0. If a ref is to be deleted, the <local ref> will be supplied as (delete) and
       the <local 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 when it reacts to git push and updates reference(s) in its
       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.

       The number of push options given on the command line of git push --push-option=... can be read from the
       environment variable GIT_PUSH_OPTION_COUNT, and the options themselves are found in GIT_PUSH_OPTION_0,
       GIT_PUSH_OPTION_1,... If it is negotiated to not use the push options phase, the environment variables
       will not be set. If the client selects to use push options, but doesn’t transmit any, the count variable
       will be set to zero, GIT_PUSH_OPTION_COUNT=0.

       See the section on "Quarantine Environment" in git-receive-pack(1) for some caveats.

   update
       This hook is invoked by git-receive-pack when it reacts to git push and updates reference(s) in its
       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 object name 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.

       In an environment that restricts the users' access only to git commands over the wire, this hook can be
       used to implement access control without relying on filesystem ownership and group membership. See git-
       shell(1) for how you might use the login shell to restrict the user’s access to only git commands.

       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 update hook, when enabled—and with hooks.allowunannotated config option unset or set to
       false—prevents unannotated tags to be pushed.

   post-receive
       This hook is invoked by git-receive-pack when it reacts to git push and updates reference(s) in its
       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 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.

       The number of push options given on the command line of git push --push-option=... can be read from the
       environment variable GIT_PUSH_OPTION_COUNT, and the options themselves are found in GIT_PUSH_OPTION_0,
       GIT_PUSH_OPTION_1,... If it is negotiated to not use the push options phase, the environment variables
       will not be set. If the client selects to use push options, but doesn’t transmit any, the count variable
       will be set to zero, GIT_PUSH_OPTION_COUNT=0.

   post-update
       This hook is invoked by git-receive-pack when it reacts to git push and updates reference(s) in its
       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.

   push-to-checkout
       This hook is invoked by git-receive-pack when it reacts to git push and updates reference(s) in its
       repository, and when the push tries to update the branch that is currently checked out and the
       receive.denyCurrentBranch configuration variable is set to updateInstead. Such a push by default is
       refused if the working tree and the index of the remote repository has any difference from the currently
       checked out commit; when both the working tree and the index match the current commit, they are updated
       to match the newly pushed tip of the branch. This hook is to be used to override the default behaviour.

       The hook receives the commit with which the tip of the current branch is going to be updated. It can exit
       with a non-zero status to refuse the push (when it does so, it must not modify the index or the working
       tree). Or it can make any necessary changes to the working tree and to the index to bring them to the
       desired state when the tip of the current branch is updated to the new commit, and exit with a zero
       status.

       For example, the hook can simply run git read-tree -u -m HEAD "$1" in order to emulate git fetch that is
       run in the reverse direction with git push, as the two-tree form of read-tree -u -m is essentially the
       same as git checkout that switches branches while keeping the local changes in the working tree that do
       not interfere with the difference between the branches.

   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(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.

           The commits are guaranteed to be listed in the order that they were processed by rebase.

   sendemail-validate
       This hook is invoked by git send-email. It takes a single parameter, the name of the file that holds the
       e-mail to be sent. Exiting with a non-zero status causes git send-email to abort before sending any
       e-mails.

   fsmonitor-watchman
       This hook is invoked when the configuration option core.fsmonitor is set to
       .git/hooks/fsmonitor-watchman. It takes two arguments, a version (currently 1) and the time in elapsed
       nanoseconds since midnight, January 1, 1970.

       The hook should output to stdout the list of all files in the working directory that may have changed
       since the requested time. The logic should be inclusive so that it does not miss any potential changes.
       The paths should be relative to the root of the working directory and be separated by a single NUL.

       It is OK to include files which have not actually changed. All changes including newly-created and
       deleted files should be included. When files are renamed, both the old and the new name should be
       included.

       Git will limit what files it checks for changes as well as which directories are checked for untracked
       files based on the path names given.

       An optimized way to tell git "all files have changed" is to return the filename /.

       The exit status determines whether git will use the data from the hook to limit its search. On error, it
       will fall back to verifying all files and folders.

GIT

       Part of the git(1) suite