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 118If you want to report something to the `git-send-pack` on the other end, 119you can simply `echo` your messages. 120 121[[update]] 122update 123------ 124 125This hook is invoked by `git-receive-pack` on the remote repository, 126which happens when a `git push` is done on a local repository. 127Just before updating the ref on the remote repository, the update hook 128is invoked. Its exit status determines the success or failure of 129the ref update. 130 131The hook executes once for each ref to be updated, and takes 132three parameters: 133 134 - the name of the ref being updated, 135 - the old object name stored in the ref, 136 - and the new objectname to be stored in the ref. 137 138A zero exit from the update hook allows the ref to be updated. 139Exiting with a non-zero status prevents `git-receive-pack` 140from updating that ref. 141 142This hook can be used to prevent 'forced' update on certain refs by 143making sure that the object name is a commit object that is a 144descendant of the commit object named by the old object name. 145That is, to enforce a "fast forward only" policy. 146 147It could also be used to log the old..new status. However, it 148does not know the entire set of branches, so it would end up 149firing one e-mail per ref when used naively, though. The 150<<post-receive,'post-receive'>> hook is more suited to that. 151 152Another use suggested on the mailing list is to use this hook to 153implement access control which is finer grained than the one 154based on filesystem group. 155 156The standard output of this hook is sent to `stderr`, so if you 157want to report something to the `git-send-pack` on the other end, 158you can simply `echo` your messages. 159 160The default 'update' hook, when enabled--and with 161`hooks.allowunannotated` config option turned on--prevents 162unannotated tags to be pushed. 163 164[[post-receive]] 165post-receive 166------------ 167 168This hook is invoked by `git-receive-pack` on the remote repository, 169which happens when a `git push` is done on a local repository. 170It executes on the remote repository once after all the refs have 171been updated. 172 173This hook executes once for the receive operation. It takes no 174arguments, but gets the same information as the `pre-receive` 175hook does on its standard input. 176 177This hook does not affect the outcome of `git-receive-pack`, as it 178is called after the real work is done. 179 180This supersedes the [[post-update]] hook in that it actually get's 181both old and new values of all the refs. 182 183If you want to report something to the `git-send-pack` on the 184other end, you can simply `echo` your messages. 185 186The default 'post-receive' hook is empty, but there is 187a sample script `post-receive-email` provided in the `contrib/hooks` 188directory in git distribution, which implements sending commit 189emails. 190 191[[post-update]] 192post-update 193----------- 194 195This hook is invoked by `git-receive-pack` on the remote repository, 196which happens when a `git push` is done on a local repository. 197It executes on the remote repository once after all the refs have 198been updated. 199 200It takes a variable number of parameters, each of which is the 201name of ref that was actually updated. 202 203This hook is meant primarily for notification, and cannot affect 204the outcome of `git-receive-pack`. 205 206The 'post-update' hook can tell what are the heads that were pushed, 207but it does not know what their original and updated values are, 208so it is a poor place to do log old..new. 209 210In general, `post-receive` hook is preferred when the hook needs 211to decide its acion on the status of the entire set of refs 212being updated, as this hook is called once per ref, with 213information only on a single ref at a time. 214 215When enabled, the default 'post-update' hook runs 216`git-update-server-info` to keep the information used by dumb 217transports (e.g., HTTP) up-to-date. If you are publishing 218a git repository that is accessible via HTTP, you should 219probably enable this hook. 220 221Both standard output and standard error output are forwarded to 222`git-send-pack` on the other end.