1Hooks used by git 2================= 3 4Hooks are little scripts you can place in `$GIT_DIR/hooks` 5directory to trigger action at certain points. When 6`git-init-db` is run, a handful example hooks are copied in the 7`hooks` directory of the new repository, but by default they are 8all disabled. To enable a hook, make it executable with `chmod +x`. 9 10This document describes the currently defined hooks. 11 12applypatch-msg 13-------------- 14 15This hook is invoked by `git-applypatch` script, which is 16typically invoked by `git-applymbox`. It takes a single 17parameter, the name of the file that holds the proposed commit 18log message. Exiting with non-zero status causes 19`git-applypatch` to abort before applying the patch. 20 21The hook is allowed to edit the message file in place, and can 22be used to normalize the message into some project standard 23format (if the project has one). It can also be used to refuse 24the commit after inspecting the message file. 25 26The default 'applypatch-msg' hook, when enabled, runs the 27'commit-msg' hook, if the latter is enabled. 28 29pre-applypatch 30-------------- 31 32This hook is invoked by `git-applypatch` script, which is 33typically invoked by `git-applymbox`. It takes no parameter, 34and is invoked after the patch is applied, but before a commit 35is made. Exiting with non-zero status causes the working tree 36after application of the patch not committed. 37 38It can be used to inspect the current working tree and refuse to 39make a commit if it does not pass certain test. 40 41The default 'pre-applypatch' hook, when enabled, runs the 42'pre-commit' hook, if the latter is enabled. 43 44post-applypatch 45--------------- 46 47This hook is invoked by `git-applypatch` script, which is 48typically invoked by `git-applymbox`. It takes no parameter, 49and is invoked after the patch is applied and a commit is made. 50 51This hook is meant primarily for notification, and cannot affect 52the outcome of `git-applypatch`. 53 54pre-commit 55---------- 56 57This hook is invoked by `git-commit`, and can be bypassed 58with `\--no-verify` option. It takes no parameter, and is 59invoked before obtaining the proposed commit log message and 60making a commit. Exiting with non-zero status from this script 61causes the `git-commit` to abort. 62 63The default 'pre-commit' hook, when enabled, catches introduction 64of lines with trailing whitespaces and aborts the commit when 65such a line is found. 66 67commit-msg 68---------- 69 70This hook is invoked by `git-commit`, and can be bypassed 71with `\--no-verify` option. It takes a single parameter, the 72name of the file that holds the proposed commit log message. 73Exiting with non-zero status causes the `git-commit` to 74abort. 75 76The hook is allowed to edit the message file in place, and can 77be used to normalize the message into some project standard 78format (if the project has one). It can also be used to refuse 79the commit after inspecting the message file. 80 81The default 'commit-msg' hook, when enabled, detects duplicate 82"Signed-off-by" lines, and aborts the commit if one is found. 83 84post-commit 85----------- 86 87This hook is invoked by `git-commit`. It takes no 88parameter, and is invoked after a commit is made. 89 90This hook is meant primarily for notification, and cannot affect 91the outcome of `git-commit`. 92 93The default 'post-commit' hook, when enabled, demonstrates how to 94send out a commit notification e-mail. 95 96update 97------ 98 99This hook is invoked by `git-receive-pack` on the remote repository, 100which happens when a `git push` is done on a local repository. 101Just before updating the ref on the remote repository, the update hook 102is invoked. Its exit status determines the success or failure of 103the ref update. 104 105The hook executes once for each ref to be updated, and takes 106three parameters: 107 108 - the name of the ref being updated, 109 - the old object name stored in the ref, 110 - and the new objectname to be stored in the ref. 111 112A zero exit from the update hook allows the ref to be updated. 113Exiting with a non-zero status prevents `git-receive-pack` 114from updating the ref. 115 116This hook can be used to prevent 'forced' update on certain refs by 117making sure that the object name is a commit object that is a 118descendant of the commit object named by the old object name. 119That is, to enforce a "fast forward only" policy. 120 121It could also be used to log the old..new status. However, it 122does not know the entire set of branches, so it would end up 123firing one e-mail per ref when used naively, though. 124 125Another use suggested on the mailing list is to use this hook to 126implement access control which is finer grained than the one 127based on filesystem group. 128 129The standard output of this hook is sent to `/dev/null`; if you 130want to report something to the `git-send-pack` on the other end, 131you can redirect your output to your `stderr`. 132 133 134post-update 135----------- 136 137This hook is invoked by `git-receive-pack` on the remote repository, 138which happens when a `git push` is done on a local repository. 139It executes on the remote repository once after all the refs have 140been updated. 141 142It takes a variable number of parameters, each of which is the 143name of ref that was actually updated. 144 145This hook is meant primarily for notification, and cannot affect 146the outcome of `git-receive-pack`. 147 148The 'post-update' hook can tell what are the heads that were pushed, 149but it does not know what their original and updated values are, 150so it is a poor place to do log old..new. 151 152When enabled, the default 'post-update' hook runs 153`git-update-server-info` to keep the information used by dumb 154transports (e.g., HTTP) up-to-date. If you are publishing 155a git repository that is accessible via HTTP, you should 156probably enable this hook. 157 158The standard output of this hook is sent to `/dev/null`; if you 159want to report something to the `git-send-pack` on the other end, 160you can redirect your output to your `stderr`.