git-hook(1)

SYNOPSIS

git hook run [--allow-unknown-hook-name] [--ignore-missing] [--to-stdin=<path>] [(-j|--jobs) <n>]
        <hook-name> [-- <hook-args>]
git hook list [--allow-unknown-hook-name] [-z] [--show-scope] <hook-name>

DESCRIPTION

A command interface for running git hooks (see githooks(5)), for use by other scripted git commands.

This command parses the default configuration files for sets of configs like so:

[hook "linter"]
  event = pre-commit
  command = ~/bin/linter --cpp20

In this example, [hook "linter"] represents one script - ~/bin/linter --cpp20 - which can be shared by many repos, and even by many hook events, if appropriate.

To add an unrelated hook which runs on a different event, for example a spell-checker for your commit messages, you would write a configuration like so:

[hook "linter"]
  event = pre-commit
  command = ~/bin/linter --cpp20
[hook "spellcheck"]
  event = commit-msg
  command = ~/bin/spellchecker

With this config, when you run git commit, first ~/bin/linter --cpp20 will have a chance to check your files to be committed (during the pre-commit hook event`), and then ~/bin/spellchecker will have a chance to check your commit message (during the commit-msg hook event).

Commands are run in the order Git encounters their associated hook.<friendly-name>.event configs during the configuration parse (see git-config(1)). Although multiple hook.linter.event configs can be added, only one hook.linter.command event is valid - Git uses "last-one-wins" to determine which command to run.

So if you wanted your linter to run when you commit as well as when you push, you would configure it like so:

[hook "linter"]
  event = pre-commit
  event = pre-push
  command = ~/bin/linter --cpp20

With this config, ~/bin/linter --cpp20 would be run by Git before a commit is generated (during pre-commit) as well as before a push is performed (during pre-push).

And if you wanted to run your linter as well as a secret-leak detector during only the "pre-commit" hook event, you would configure it instead like so:

[hook "linter"]
  event = pre-commit
  command = ~/bin/linter --cpp20
[hook "no-leaks"]
  event = pre-commit
  command = ~/bin/leak-detector

With this config, before a commit is generated (during pre-commit), Git would first start ~/bin/linter --cpp20 and second start ~/bin/leak-detector. It would evaluate the output of each when deciding whether to proceed with the commit.

For a full list of hook events which you can set your hook.<friendly-name>.event to, and how hooks are invoked during those events, see githooks(5).

Git will ignore any hook.<friendly-name>.event that specifies an event it doesn’t recognize. This is intended so that tools which wrap Git can use the hook infrastructure to run their own hooks; see "WRAPPERS" for more guidance.

In general, when instructions suggest adding a script to .git/hooks/<hook-event>, you can specify it in the config instead by running:

git config set hook.<some-name>.command <path-to-script>
git config set --append hook.<some-name>.event <hook-event>

This way you can share the script between multiple repos. That is, cp ~/my-script.sh ~/project/.git/hooks/pre-commit would become:

git config set hook.my-script.command ~/my-script.sh
git config set --append hook.my-script.event pre-commit

SUBCOMMANDS

run: Runs hooks configured for <hook-name>, in the order they are discovered during the config parse. The default <hook-name> from the hookdir is run last. See githooks(5) for supported hook names.

Any positional arguments to the hook should be passed after a mandatory -- (or --end-of-options, see gitcli(7)). See githooks(5) for arguments hooks might expect (if any).
list [-z] [--show-scope]: Print a list of hooks which will be run on <hook-name> event. If no hooks are configured for that event, print a warning and return 1. Use -z to terminate output lines with NUL instead of newlines.

OPTIONS

--allow-unknown-hook-name: By default git hook run and git hook list will bail out when <hook-name> is not a hook event known to Git (see githooks(5) for the list of known hooks). This is meant to help catch typos such as prereceive when pre-receive was intended. Pass this flag to allow unknown hook names.
--to-stdin: For "run"; specify a file which will be streamed into the hook’s stdin. The hook will receive the entire file from beginning to EOF.
--ignore-missing: Ignore any missing hook by quietly returning zero. Used for tools that want to do a blind one-shot run of a hook that may or may not be present.
-z: Terminate "list" output lines with NUL instead of newlines.
--show-scope: For "list"; prefix each configured hook’s friendly name with a tab-separated config scope (e.g. local, global, system), mirroring the output style of git config --show-scope. Traditional hooks from the hookdir are unaffected.
-j
--jobs: Only valid for run.

Specify how many hooks to run simultaneously. If this flag is not specified, the value of the hook.jobs config is used, see git-config(1). If neither is specified, defaults to 1 (serial execution).

When greater than 1, it overrides the per-hook hook.<friendly-name>.parallel setting, allowing all hooks for the event to run concurrently, even if they are not individually marked as parallel.

Some hooks always run sequentially regardless of this flag or the hook.jobs config, because git knows they cannot safely run in parallel: applypatch-msg, pre-commit, prepare-commit-msg, commit-msg, post-commit, post-checkout, and push-to-checkout.

WRAPPERS

git hook run has been designed to make it easy for tools which wrap Git to configure and execute hooks using the Git hook infrastructure. It is possible to provide arguments and stdin via the command line, as well as specifying parallel or series execution if the user has provided multiple hooks.

Assuming your wrapper wants to support a hook named "mywrapper-start-tests", you can have your users specify their hooks like so:

[hook "setup-test-dashboard"]
  event = mywrapper-start-tests
  command = ~/mywrapper/setup-dashboard.py --tap

Then, in your mywrapper tool, you can invoke any users' configured hooks by running:

git hook run --allow-unknown-hook-name mywrapper-start-tests \
  # providing something to stdin
  --stdin some-tempfile-123 \
  # execute multiple hooks in parallel
  --jobs 3 \
  # plus some arguments of your own...
  -- \
  --testname bar \
  baz

Take care to name your wrapper’s hook events in a way which is unlikely to overlap with Git’s native hooks (see githooks(5)) - a hook event named mywrappertool-validate-commit is much less likely to be added to native Git than a hook event named validate-commit. If Git begins to use a hook event named the same thing as your wrapper hook, it may invoke your users' hooks in unintended and unsupported ways.

CONFIGURATION

hook.<friendly-name>.command

The command to execute for hook.<friendly-name>. <friendly-name> is a unique name that identifies this hook. The hook events that trigger the command are configured with hook.<friendly-name>.event. The value can be an executable path or a shell oneliner. If more than one value is specified for the same <friendly-name>, only the last value parsed is used. See git-hook(1).

hook.<friendly-name>.event

The hook events that trigger hook.<friendly-name>. The value is the name of a hook event, like "pre-commit" or "update". (See githooks(5) for a complete list of hook events.) On the specified event, the associated hook.<friendly-name>.command is executed. This is a multi-valued key. To run hook.<friendly-name> on multiple events, specify the key more than once. An empty value resets the list of events, clearing any previously defined events for hook.<friendly-name>. See git-hook(1).

The <friendly-name> must not be the same as a known hook event name (e.g. do not use hook.pre-commit.event). Using a known event name as a friendly-name is a fatal error because it creates an ambiguity with hook.<event>.enabled and hook.<event>.jobs. For unknown event names, a warning is issued when <friendly-name> matches the event value.

hook.<friendly-name>.enabled

Whether the hook hook.<friendly-name> is enabled. Defaults to true. Set to false to disable the hook without removing its configuration. This is particularly useful when a hook is defined in a system or global config file and needs to be disabled for a specific repository. See git-hook(1).

hook.<friendly-name>.parallel

Whether the hook hook.<friendly-name> may run in parallel with other hooks for the same event. Defaults to false. Set to true only when the hook script is safe to run concurrently with other hooks for the same event. If any hook for an event does not have this set to true, all hooks for that event run sequentially regardless of hook.jobs. Only configured (named) hooks need to declare this. Traditional hooks found in the hooks directory do not need to, and run in parallel when the effective job count is greater than 1. See git-hook(1).

hook.<event>.enabled

Switch to enable or disable all hooks for the <event> hook event. When set to false, no hooks fire for that event, regardless of any per-hook hook.<friendly-name>.enabled settings. Defaults to true. See git-hook(1).

Note on naming: <event> must be the event name (e.g. pre-commit), not a hook friendly-name. Since using a known event name as a friendly-name is disallowed (see hook.<friendly-name>.event above), there is no ambiguity between event-level and per-hook .enabled settings for known events. For unknown events, if a friendly-name matches the event name despite the warning, .enabled is treated as per-hook only.

hook.<event>.jobs

Specifies how many hooks can be run simultaneously for the <event> hook event (e.g. hook.post-receive.jobs = 4). Overrides hook.jobs for this specific event. The same parallelism restrictions apply: this setting has no effect unless all configured hooks for the event have hook.<friendly-name>.parallel set to true. Set to -1 to use the number of available CPU cores. Must be a positive integer or -1; zero is rejected with a warning. See git-hook(1).

Note on naming: although this key resembles hook.<friendly-name>.* (a per-hook setting), <event> must be the event name, not a hook friendly name. The key component is stored literally and looked up by event name at runtime with no translation between the two namespaces. A key like hook.my-hook.jobs is stored under "my-hook" but the lookup at runtime uses the event name (e.g. "post-receive"), so hook.my-hook.jobs is silently ignored even when my-hook is registered for that event. Use hook.post-receive.jobs or any other valid event name when setting hook.<event>.jobs.

hook.jobs

Specifies how many hooks can be run simultaneously during parallelized hook execution. If unspecified, defaults to 1 (serial execution). Set to -1 to use the number of available CPU cores. Can be overridden on a per-event basis with hook.<event>.jobs. Some hooks always run sequentially regardless of this setting because they operate on shared data and cannot safely be parallelized:

applypatch-msg
prepare-commit-msg
commit-msg: Receive a commit message file and may rewrite it in place.
pre-commit
post-checkout
push-to-checkout
post-commit: Access the working tree, index, or repository state.

This setting has no effect unless all configured hooks for the event have hook.<friendly-name>.parallel set to true.

For pre-push hooks, which normally keep stdout and stderr separate, setting this to a value greater than 1 (or passing -j) will merge stdout into stderr to allow correct de-interleaving of parallel output.

GIT

Part of the git(1) suite

git-hook(1) Manual Page

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