hooks.txt - external/gitster/git-htmldocs - Git at Google

 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-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. 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-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.

 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`.

 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`.

 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`.

 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-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:

  <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,'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]]
 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,'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.

 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,'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,'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]]
 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,'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.
	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-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. 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-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.

	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`.

	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`.

	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`.

	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-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:

	<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,'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]]
	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,'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.

	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,'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,'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]]
	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,'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.