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` 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 93[[pre-receive]] 94pre-receive 95----------- 96 97This hook is invoked by `git-receive-pack` on the remote repository, 98which happens when a `git push` is done on a local repository. 99Just before starting to update refs on the remote repository, the 100pre-receive hook is invoked. Its exit status determines the success 101or failure of the update. 102 103This hook executes once for the receive operation. It takes no 104arguments, but for each ref to be updated it receives on standard 105input a line of the format: 106 107 <old-value> SP <new-value> SP <ref-name> LF 108 109where `<old-value>` is the old object name stored in the ref, 110`<new-value>` is the new object name to be stored in the ref and 111`<ref-name>` is the full name of the ref. 112When creating a new ref, `<old-value>` is 40 `0`. 113 114If the hook exits with non-zero status, none of the refs will be 115updated. If the hook exits with zero, updating of individual refs can 116still be prevented by the <<update,'update'>> hook. 117 118Both standard output and standard error output are forwarded to 119`git-send-pack` on the other end, so you can simply `echo` messages 120for the user. 121 122[[update]] 123update 124------ 125 126This hook is invoked by `git-receive-pack` on the remote repository, 127which happens when a `git push` is done on a local repository. 128Just before updating the ref on the remote repository, the update hook 129is invoked. Its exit status determines the success or failure of 130the ref update. 131 132The hook executes once for each ref to be updated, and takes 133three parameters: 134 135 - the name of the ref being updated, 136 - the old object name stored in the ref, 137 - and the new objectname to be stored in the ref. 138 139A zero exit from the update hook allows the ref to be updated. 140Exiting with a non-zero status prevents `git-receive-pack` 141from updating that ref. 142 143This hook can be used to prevent 'forced' update on certain refs by 144making sure that the object name is a commit object that is a 145descendant of the commit object named by the old object name. 146That is, to enforce a "fast forward only" policy. 147 148It could also be used to log the old..new status. However, it 149does not know the entire set of branches, so it would end up 150firing one e-mail per ref when used naively, though. The 151<<post-receive,'post-receive'>> hook is more suited to that. 152 153Another use suggested on the mailing list is to use this hook to 154implement access control which is finer grained than the one 155based on filesystem group. 156 157Both standard output and standard error output are forwarded to 158`git-send-pack` on the other end, so you can simply `echo` messages 159for the user. 160 161The default 'update' hook, when enabled--and with 162`hooks.allowunannotated` config option turned on--prevents 163unannotated tags to be pushed. 164 165[[post-receive]] 166post-receive 167------------ 168 169This hook is invoked by `git-receive-pack` on the remote repository, 170which happens when a `git push` is done on a local repository. 171It executes on the remote repository once after all the refs have 172been updated. 173 174This hook executes once for the receive operation. It takes no 175arguments, but gets the same information as the 176<<pre-receive,'pre-receive'>> 177hook does on its standard input. 178 179This hook does not affect the outcome of `git-receive-pack`, as it 180is called after the real work is done. 181 182This supersedes the <<post-update,'post-update'>> hook in that it get's 183both old and new values of all the refs in addition to their 184names. 185 186Both standard output and standard error output are forwarded to 187`git-send-pack` on the other end, so you can simply `echo` messages 188for the user. 189 190The default 'post-receive' hook is empty, but there is 191a sample script `post-receive-email` provided in the `contrib/hooks` 192directory in git distribution, which implements sending commit 193emails. 194 195[[post-update]] 196post-update 197----------- 198 199This hook is invoked by `git-receive-pack` on the remote repository, 200which happens when a `git push` is done on a local repository. 201It executes on the remote repository once after all the refs have 202been updated. 203 204It takes a variable number of parameters, each of which is the 205name of ref that was actually updated. 206 207This hook is meant primarily for notification, and cannot affect 208the outcome of `git-receive-pack`. 209 210The 'post-update' hook can tell what are the heads that were pushed, 211but it does not know what their original and updated values are, 212so it is a poor place to do log old..new. The 213<<post-receive,'post-receive'>> hook does get both original and 214updated values of the refs. You might consider it instead if you need 215them. 216 217When enabled, the default 'post-update' hook runs 218`git-update-server-info` to keep the information used by dumb 219transports (e.g., HTTP) up-to-date. If you are publishing 220a git repository that is accessible via HTTP, you should 221probably enable this hook. 222 223Both standard output and standard error output are forwarded to 224`git-send-pack` on the other end, so you can simply `echo` messages 225for the user.