1githooks(5) 2=========== 3 4NAME 5---- 6githooks - Hooks used by git 7 8SYNOPSIS 9-------- 10$GIT_DIR/hooks/* 11 12 13DESCRIPTION 14----------- 15 16Hooks are little scripts you can place in `$GIT_DIR/hooks` 17directory to trigger action at certain points. When 18'git-init' is run, a handful of example hooks are copied into the 19`hooks` directory of the new repository, but by default they are 20all disabled. To enable a hook, rename it by removing its `.sample` 21suffix. 22 23NOTE: It is also a requirement for a given hook to be executable. 24However - in a freshly initialized repository - the `.sample` files are 25executable by default. 26 27This document describes the currently defined hooks. 28 29HOOKS 30----- 31 32applypatch-msg 33~~~~~~~~~~~~~~ 34 35This hook is invoked by 'git-am' script. It takes a single 36parameter, the name of the file that holds the proposed commit 37log message. Exiting with non-zero status causes 38'git-am' to abort before applying the patch. 39 40The hook is allowed to edit the message file in place, and can 41be used to normalize the message into some project standard 42format (if the project has one). It can also be used to refuse 43the commit after inspecting the message file. 44 45The default 'applypatch-msg' hook, when enabled, runs the 46'commit-msg' hook, if the latter is enabled. 47 48pre-applypatch 49~~~~~~~~~~~~~~ 50 51This hook is invoked by 'git-am'. It takes no parameter, and is 52invoked after the patch is applied, but before a commit is made. 53 54If it exits with non-zero status, then the working tree will not be 55committed after applying the patch. 56 57It can be used to inspect the current working tree and refuse to 58make a commit if it does not pass certain test. 59 60The default 'pre-applypatch' hook, when enabled, runs the 61'pre-commit' hook, if the latter is enabled. 62 63post-applypatch 64~~~~~~~~~~~~~~~ 65 66This hook is invoked by 'git-am'. It takes no parameter, 67and is invoked after the patch is applied and a commit is made. 68 69This hook is meant primarily for notification, and cannot affect 70the outcome of 'git-am'. 71 72pre-commit 73~~~~~~~~~~ 74 75This hook is invoked by 'git-commit', and can be bypassed 76with `\--no-verify` option. It takes no parameter, and is 77invoked before obtaining the proposed commit log message and 78making a commit. Exiting with non-zero status from this script 79causes the 'git-commit' to abort. 80 81The default 'pre-commit' hook, when enabled, catches introduction 82of lines with trailing whitespaces and aborts the commit when 83such a line is found. 84 85All the 'git-commit' hooks are invoked with the environment 86variable `GIT_EDITOR=:` if the command will not bring up an editor 87to modify the commit message. 88 89prepare-commit-msg 90~~~~~~~~~~~~~~~~~~ 91 92This hook is invoked by 'git-commit' right after preparing the 93default log message, and before the editor is started. 94 95It takes one to three parameters. The first is the name of the file 96that contains the commit log message. The second is the source of the commit 97message, and can be: `message` (if a `-m` or `-F` option was 98given); `template` (if a `-t` option was given or the 99configuration option `commit.template` is set); `merge` (if the 100commit is a merge or a `.git/MERGE_MSG` file exists); `squash` 101(if a `.git/SQUASH_MSG` file exists); or `commit`, followed by 102a commit SHA1 (if a `-c`, `-C` or `\--amend` option was given). 103 104If the exit status is non-zero, 'git-commit' will abort. 105 106The purpose of the hook is to edit the message file in place, and 107it is not suppressed by the `\--no-verify` option. A non-zero exit 108means a failure of the hook and aborts the commit. It should not 109be used as replacement for pre-commit hook. 110 111The sample `prepare-commit-msg` hook that comes with git comments 112out the `Conflicts:` part of a merge's commit message. 113 114commit-msg 115~~~~~~~~~~ 116 117This hook is invoked by 'git-commit', and can be bypassed 118with `\--no-verify` option. It takes a single parameter, the 119name of the file that holds the proposed commit log message. 120Exiting with non-zero status causes the 'git-commit' to 121abort. 122 123The hook is allowed to edit the message file in place, and can 124be used to normalize the message into some project standard 125format (if the project has one). It can also be used to refuse 126the commit after inspecting the message file. 127 128The default 'commit-msg' hook, when enabled, detects duplicate 129"Signed-off-by" lines, and aborts the commit if one is found. 130 131post-commit 132~~~~~~~~~~~ 133 134This hook is invoked by 'git-commit'. It takes no 135parameter, and is invoked after a commit is made. 136 137This hook is meant primarily for notification, and cannot affect 138the outcome of 'git-commit'. 139 140pre-rebase 141~~~~~~~~~~ 142 143This hook is called by 'git-rebase' and can be used to prevent a branch 144from getting rebased. 145 146 147post-checkout 148~~~~~~~~~~~~~ 149 150This hook is invoked when a 'git-checkout' is run after having updated the 151worktree. The hook is given three parameters: the ref of the previous HEAD, 152the ref of the new HEAD (which may or may not have changed), and a flag 153indicating whether the checkout was a branch checkout (changing branches, 154flag=1) or a file checkout (retrieving a file from the index, flag=0). 155This hook cannot affect the outcome of 'git-checkout'. 156 157It is also run after 'git-clone', unless the --no-checkout (-n) option is 158used. The first parameter given to the hook is the null-ref, the second the 159ref of the new HEAD and the flag is always 1. 160 161This hook can be used to perform repository validity checks, auto-display 162differences from the previous HEAD if different, or set working dir metadata 163properties. 164 165post-merge 166~~~~~~~~~~ 167 168This hook is invoked by 'git-merge', which happens when a 'git-pull' 169is done on a local repository. The hook takes a single parameter, a status 170flag specifying whether or not the merge being done was a squash merge. 171This hook cannot affect the outcome of 'git-merge' and is not executed, 172if the merge failed due to conflicts. 173 174This hook can be used in conjunction with a corresponding pre-commit hook to 175save and restore any form of metadata associated with the working tree 176(eg: permissions/ownership, ACLS, etc). See contrib/hooks/setgitperms.perl 177for an example of how to do this. 178 179[[pre-receive]] 180pre-receive 181~~~~~~~~~~~ 182 183This hook is invoked by 'git-receive-pack' on the remote repository, 184which happens when a 'git-push' is done on a local repository. 185Just before starting to update refs on the remote repository, the 186pre-receive hook is invoked. Its exit status determines the success 187or failure of the update. 188 189This hook executes once for the receive operation. It takes no 190arguments, but for each ref to be updated it receives on standard 191input a line of the format: 192 193 <old-value> SP <new-value> SP <ref-name> LF 194 195where `<old-value>` is the old object name stored in the ref, 196`<new-value>` is the new object name to be stored in the ref and 197`<ref-name>` is the full name of the ref. 198When creating a new ref, `<old-value>` is 40 `0`. 199 200If the hook exits with non-zero status, none of the refs will be 201updated. If the hook exits with zero, updating of individual refs can 202still be prevented by the <<update,'update'>> hook. 203 204Both standard output and standard error output are forwarded to 205'git-send-pack' on the other end, so you can simply `echo` messages 206for the user. 207 208[[update]] 209update 210~~~~~~ 211 212This hook is invoked by 'git-receive-pack' on the remote repository, 213which happens when a 'git-push' is done on a local repository. 214Just before updating the ref on the remote repository, the update hook 215is invoked. Its exit status determines the success or failure of 216the ref update. 217 218The hook executes once for each ref to be updated, and takes 219three parameters: 220 221 - the name of the ref being updated, 222 - the old object name stored in the ref, 223 - and the new objectname to be stored in the ref. 224 225A zero exit from the update hook allows the ref to be updated. 226Exiting with a non-zero status prevents 'git-receive-pack' 227from updating that ref. 228 229This hook can be used to prevent 'forced' update on certain refs by 230making sure that the object name is a commit object that is a 231descendant of the commit object named by the old object name. 232That is, to enforce a "fast forward only" policy. 233 234It could also be used to log the old..new status. However, it 235does not know the entire set of branches, so it would end up 236firing one e-mail per ref when used naively, though. The 237<<post-receive,'post-receive'>> hook is more suited to that. 238 239Another use suggested on the mailing list is to use this hook to 240implement access control which is finer grained than the one 241based on filesystem group. 242 243Both standard output and standard error output are forwarded to 244'git-send-pack' on the other end, so you can simply `echo` messages 245for the user. 246 247The default 'update' hook, when enabled--and with 248`hooks.allowunannotated` config option turned on--prevents 249unannotated tags to be pushed. 250 251[[post-receive]] 252post-receive 253~~~~~~~~~~~~ 254 255This hook is invoked by 'git-receive-pack' on the remote repository, 256which happens when a 'git-push' is done on a local repository. 257It executes on the remote repository once after all the refs have 258been updated. 259 260This hook executes once for the receive operation. It takes no 261arguments, but gets the same information as the 262<<pre-receive,'pre-receive'>> 263hook does on its standard input. 264 265This hook does not affect the outcome of 'git-receive-pack', as it 266is called after the real work is done. 267 268This supersedes the <<post-update,'post-update'>> hook in that it gets 269both old and new values of all the refs in addition to their 270names. 271 272Both standard output and standard error output are forwarded to 273'git-send-pack' on the other end, so you can simply `echo` messages 274for the user. 275 276The default 'post-receive' hook is empty, but there is 277a sample script `post-receive-email` provided in the `contrib/hooks` 278directory in git distribution, which implements sending commit 279emails. 280 281[[post-update]] 282post-update 283~~~~~~~~~~~ 284 285This hook is invoked by 'git-receive-pack' on the remote repository, 286which happens when a 'git-push' is done on a local repository. 287It executes on the remote repository once after all the refs have 288been updated. 289 290It takes a variable number of parameters, each of which is the 291name of ref that was actually updated. 292 293This hook is meant primarily for notification, and cannot affect 294the outcome of 'git-receive-pack'. 295 296The 'post-update' hook can tell what are the heads that were pushed, 297but it does not know what their original and updated values are, 298so it is a poor place to do log old..new. The 299<<post-receive,'post-receive'>> hook does get both original and 300updated values of the refs. You might consider it instead if you need 301them. 302 303When enabled, the default 'post-update' hook runs 304'git-update-server-info' to keep the information used by dumb 305transports (e.g., HTTP) up-to-date. If you are publishing 306a git repository that is accessible via HTTP, you should 307probably enable this hook. 308 309Both standard output and standard error output are forwarded to 310'git-send-pack' on the other end, so you can simply `echo` messages 311for the user. 312 313pre-auto-gc 314~~~~~~~~~~~ 315 316This hook is invoked by 'git-gc --auto'. It takes no parameter, and 317exiting with non-zero status from this script causes the 'git-gc --auto' 318to abort. 319 320GIT 321--- 322Part of the linkgit:git[1] suite