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diff --git a/Documentation/git-update-ref.adoc b/Documentation/git-update-ref.adoc new file mode 100644 index 0000000000..9310ce9768 --- /dev/null +++ b/Documentation/git-update-ref.adoc @@ -0,0 +1,209 @@ +git-update-ref(1) +================= + +NAME +---- +git-update-ref - Update the object name stored in a ref safely + +SYNOPSIS +-------- +[synopsis] +git update-ref [-m <reason>] [--no-deref] -d <ref> [<old-oid>] +git update-ref [-m <reason>] [--no-deref] [--create-reflog] <ref> <new-oid> [<old-oid>] +git update-ref [-m <reason>] [--no-deref] --stdin [-z] [--batch-updates] + +DESCRIPTION +----------- +Given two arguments, stores the <new-oid> in the <ref>, possibly +dereferencing the symbolic refs. E.g. `git update-ref HEAD +<new-oid>` updates the current branch head to the new object. + +Given three arguments, stores the <new-oid> in the <ref>, +possibly dereferencing the symbolic refs, after verifying that +the current value of the <ref> matches <old-oid>. +E.g. `git update-ref refs/heads/master <new-oid> <old-oid>` +updates the master branch head to <new-oid> only if its current +value is <old-oid>. You can specify 40 "0" or an empty string +as <old-oid> to make sure that the ref you are creating does +not exist. + +The final arguments are object names; this command without any options +does not support updating a symbolic ref to point to another ref (see +linkgit:git-symbolic-ref[1]). But `git update-ref --stdin` does have +the `symref-*` commands so that regular refs and symbolic refs can be +committed in the same transaction. + +If --no-deref is given, <ref> itself is overwritten, rather than +the result of following the symbolic pointers. + +With `-d`, it deletes the named <ref> after verifying that it +still contains <old-oid>. + +With `--stdin`, update-ref reads instructions from standard input and +performs all modifications together. Specify commands of the form: + + update SP <ref> SP <new-oid> [SP <old-oid>] LF + create SP <ref> SP <new-oid> LF + delete SP <ref> [SP <old-oid>] LF + verify SP <ref> [SP <old-oid>] LF + symref-update SP <ref> SP <new-target> [SP (ref SP <old-target> | oid SP <old-oid>)] LF + symref-create SP <ref> SP <new-target> LF + symref-delete SP <ref> [SP <old-target>] LF + symref-verify SP <ref> [SP <old-target>] LF + option SP <opt> LF + start LF + prepare LF + commit LF + abort LF + +With `--create-reflog`, update-ref will create a reflog for each ref +even if one would not ordinarily be created. + +With `--batch-updates`, update-ref executes the updates in a batch but allows +individual updates to fail due to invalid or incorrect user input, applying only +the successful updates. However, system-related errors—such as I/O failures or +memory issues—will result in a full failure of all batched updates. Any failed +updates will be reported in the following format: + + rejected SP (<old-oid> | <old-target>) SP (<new-oid> | <new-target>) SP <rejection-reason> LF + +Quote fields containing whitespace as if they were strings in C source +code; i.e., surrounded by double-quotes and with backslash escapes. +Use 40 "0" characters or the empty string to specify a zero value. To +specify a missing value, omit the value and its preceding SP entirely. + +Alternatively, use `-z` to specify in NUL-terminated format, without +quoting: + + update SP <ref> NUL <new-oid> NUL [<old-oid>] NUL + create SP <ref> NUL <new-oid> NUL + delete SP <ref> NUL [<old-oid>] NUL + verify SP <ref> NUL [<old-oid>] NUL + symref-update SP <ref> NUL <new-target> [NUL (ref NUL <old-target> | oid NUL <old-oid>)] NUL + symref-create SP <ref> NUL <new-target> NUL + symref-delete SP <ref> [NUL <old-target>] NUL + symref-verify SP <ref> [NUL <old-target>] NUL + option SP <opt> NUL + start NUL + prepare NUL + commit NUL + abort NUL + +In this format, use 40 "0" to specify a zero value, and use the empty +string to specify a missing value. + +In either format, values can be specified in any form that Git +recognizes as an object name. Commands in any other format or a +repeated <ref> produce an error. Command meanings are: + +update:: + Set <ref> to <new-oid> after verifying <old-oid>, if given. + Specify a zero <new-oid> to ensure the ref does not exist + after the update and/or a zero <old-oid> to make sure the + ref does not exist before the update. + +create:: + Create <ref> with <new-oid> after verifying that it does not + exist. The given <new-oid> may not be zero. + +delete:: + Delete <ref> after verifying that it exists with <old-oid>, if + given. If given, <old-oid> may not be zero. + +symref-update:: + Set <ref> to <new-target> after verifying <old-target> or <old-oid>, + if given. Specify a zero <old-oid> to ensure that the ref does not + exist before the update. + +verify:: + Verify <ref> against <old-oid> but do not change it. If + <old-oid> is zero or missing, the ref must not exist. + +symref-create: + Create symbolic ref <ref> with <new-target> after verifying that + it does not exist. + +symref-delete:: + Delete <ref> after verifying that it exists with <old-target>, if given. + +symref-verify:: + Verify symbolic <ref> against <old-target> but do not change it. + If <old-target> is missing, the ref must not exist. Can only be + used in `no-deref` mode. + +option:: + Modify the behavior of the next command naming a <ref>. + The only valid option is `no-deref` to avoid dereferencing + a symbolic ref. + +start:: + Start a transaction. In contrast to a non-transactional session, a + transaction will automatically abort if the session ends without an + explicit commit. This command may create a new empty transaction when + the current one has been committed or aborted already. + +prepare:: + Prepare to commit the transaction. This will create lock files for all + queued reference updates. If one reference could not be locked, the + transaction will be aborted. + +commit:: + Commit all reference updates queued for the transaction, ending the + transaction. + +abort:: + Abort the transaction, releasing all locks if the transaction is in + prepared state. + +If all <ref>s can be locked with matching <old-oid>s +simultaneously, all modifications are performed. Otherwise, no +modifications are performed. Note that while each individual +<ref> is updated or deleted atomically, a concurrent reader may +still see a subset of the modifications. + +LOGGING UPDATES +--------------- +If config parameter "core.logAllRefUpdates" is true and the ref is one +under "refs/heads/", "refs/remotes/", "refs/notes/", or a pseudoref +like HEAD or ORIG_HEAD; or the file "$GIT_DIR/logs/<ref>" exists then +`git update-ref` will append a line to the log file +"$GIT_DIR/logs/<ref>" (dereferencing all symbolic refs before creating +the log name) describing the change in ref value. Log lines are +formatted as: + + oldsha1 SP newsha1 SP committer LF + +Where "oldsha1" is the 40 character hexadecimal value previously +stored in <ref>, "newsha1" is the 40 character hexadecimal value of +<new-oid> and "committer" is the committer's name, email address +and date in the standard Git committer ident format. + +Optionally with -m: + + oldsha1 SP newsha1 SP committer TAB message LF + +Where all fields are as described above and "message" is the +value supplied to the -m option. + +An update will fail (without changing <ref>) if the current user is +unable to create a new log file, append to the existing log file +or does not have committer information available. + +NOTES +----- + +Symbolic refs were initially implemented using symbolic links. This is +now deprecated since not all filesystems support symbolic links. + +This command follows *real* symlinks only if they start with "refs/": +otherwise it will just try to read them and update them as a regular +file (i.e. it will allow the filesystem to follow them, but will +overwrite such a symlink to somewhere else with a regular filename). + +SEE ALSO +-------- +linkgit:git-symbolic-ref[1] + +GIT +--- +Part of the linkgit:git[1] suite |