Setup and Config
Getting and Creating Projects
Branching and Merging
Sharing and Updating Projects
Inspection and Comparison
- 18.104.22.168 → 2.0.3 no changes
- 1.8.5 11/27/13
- 22.214.171.124 → 126.96.36.199 no changes
- 188.8.131.52 04/07/13
- 184.108.40.206 → 220.127.116.11 no changes
- 18.104.22.168 08/24/11
- 22.214.171.124 → 1.7.6 no changes
- 1.7.5 04/24/11
- 126.96.36.199 → 188.8.131.52 no changes
- 1.6.0 08/17/08
- 184.108.40.206 → 220.127.116.11 no changes
- 1.5.6 06/18/08
- 18.104.22.168 → 22.214.171.124 no changes
- 1.5.4 02/02/08
- 126.96.36.199 → 188.8.131.52 no changes
- 1.5.3 09/02/07
- 184.108.40.206 → 220.127.116.11 no changes
- 1.5.0 02/14/07
- 18.104.22.168 → 22.214.171.124 no changes
- 1.4.4 11/15/06
git-update-ref(1) Manual Page
git-update-ref - Update the object name stored in a ref safely
git update-ref [-m <reason>] (-d <ref> [<oldvalue>] | [--no-deref] <ref> <newvalue> [<oldvalue>] | --stdin [-z])
Given two arguments, stores the <newvalue> in the <ref>, possibly dereferencing the symbolic refs. E.g. git update-ref HEAD <newvalue> updates the current branch head to the new object.
Given three arguments, stores the <newvalue> in the <ref>, possibly dereferencing the symbolic refs, after verifying that the current value of the <ref> matches <oldvalue>. E.g. git update-ref refs/heads/master <newvalue> <oldvalue> updates the master branch head to <newvalue> only if its current value is <oldvalue>. You can specify 40 "0" or an empty string as <oldvalue> to make sure that the ref you are creating does not exist.
It also allows a "ref" file to be a symbolic pointer to another ref file by starting with the four-byte header sequence of "ref:".
More importantly, it allows the update of a ref file to follow these symbolic pointers, whether they are symlinks or these "regular file symbolic refs". It 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).
If --no-deref is given, <ref> itself is overwritten, rather than the result of following the symbolic pointers.
In general, using
git update-ref HEAD "$head"
should be a lot safer than doing
echo "$head" > "$GIT_DIR/HEAD"
both from a symlink following standpoint and an error checking standpoint. The "refs/" rule for symlinks means that symlinks that point to "outside" the tree are safe: they'll be followed for reading but not for writing (so we'll never write through a ref symlink to some other tree, if you have copied a whole archive by creating a symlink tree).
With -d flag, it deletes the named <ref> after verifying it still contains <oldvalue>.
With --stdin, update-ref reads instructions from standard input and performs all modifications together. Specify commands of the form:
update SP <ref> SP <newvalue> [SP <oldvalue>] LF create SP <ref> SP <newvalue> LF delete SP <ref> [SP <oldvalue>] LF verify SP <ref> [SP <oldvalue>] LF option SP <opt> LF
Quote fields containing whitespace as if they were strings in C source code. Alternatively, use -z to specify commands without quoting:
update SP <ref> NUL <newvalue> NUL [<oldvalue>] NUL create SP <ref> NUL <newvalue> NUL delete SP <ref> NUL [<oldvalue>] NUL verify SP <ref> NUL [<oldvalue>] NUL option SP <opt> NUL
Lines of any other format or a repeated <ref> produce an error. Command meanings are:
Set <ref> to <newvalue> after verifying <oldvalue>, if given. Specify a zero <newvalue> to ensure the ref does not exist after the update and/or a zero <oldvalue> to make sure the ref does not exist before the update.
Create <ref> with <newvalue> after verifying it does not exist. The given <newvalue> may not be zero.
Delete <ref> after verifying it exists with <oldvalue>, if given. If given, <oldvalue> may not be zero.
Verify <ref> against <oldvalue> but do not change it. If <oldvalue> zero or missing, the ref must not exist.
Modify behavior of the next command naming a <ref>. The only valid option is no-deref to avoid dereferencing a symbolic ref.
Use 40 "0" or the empty string to specify a zero value, except that with -z an empty <oldvalue> is considered missing.
If all <ref>s can be locked with matching <oldvalue>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.
If config parameter "core.logAllRefUpdates" is true and the ref is one under "refs/heads/", "refs/remotes/", "refs/notes/", or the symbolic ref 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 <newvalue> 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.
Part of the git(1) suite