git-rev-parse.txt
git-rev-parse(1)
================
NAME
----
git-rev-parse - Pick out and massage parameters
SYNOPSIS
--------
'git-rev-parse' [ --option ] <args>...
DESCRIPTION
-----------
Many git porcelainish commands take mixture of flags
(i.e. parameters that begin with a dash '-') and parameters
meant for underlying `git-rev-list` command they use internally
and flags and parameters for other commands they use as the
downstream of `git-rev-list`. This command is used to
distinguish between them.
OPTIONS
-------
--revs-only::
Do not output flags and parameters not meant for
`git-rev-list` command.
--no-revs::
Do not output flags and parameters meant for
`git-rev-list` command.
--flags::
Do not output non-flag parameters.
--no-flags::
Do not output flag parameters.
--default <arg>::
If there is no parameter given by the user, use `<arg>`
instead.
--verify::
The parameter given must be usable as a single, valid
object name. Otherwise barf and abort.
--sq::
Usually the output is made one line per flag and
parameter. This option makes output a single line,
properly quoted for consumption by shell. Useful when
you expect your parameter to contain whitespaces and
newlines (e.g. when using pickaxe `-S` with
`git-diff-\*`).
--not::
When showing object names, prefix them with '{caret}' and
strip '{caret}' prefix from the object names that already have
one.
--symbolic::
Usually the object names are output in SHA1 form (with
possible '{caret}' prefix); this option makes them output in a
form as close to the original input as possible.
--all::
Show all refs found in `$GIT_DIR/refs`.
--branches::
Show branch refs found in `$GIT_DIR/refs/heads`.
--tags::
Show tag refs found in `$GIT_DIR/refs/tags`.
--remotes::
Show tag refs found in `$GIT_DIR/refs/remotes`.
--show-prefix::
When the command is invoked from a subdirectory, show the
path of the current directory relative to the top-level
directory.
--show-cdup::
When the command is invoked from a subdirectory, show the
path of the top-level directory relative to the current
directory (typically a sequence of "../", or an empty string).
--git-dir::
Show `$GIT_DIR` if defined else show the path to the .git directory.
--short, --short=number::
Instead of outputting the full SHA1 values of object names try to
abbreviate them to a shorter unique name. When no length is specified
7 is used. The minimum length is 4.
--since=datestring, --after=datestring::
Parses the date string, and outputs corresponding
--max-age= parameter for git-rev-list command.
--until=datestring, --before=datestring::
Parses the date string, and outputs corresponding
--min-age= parameter for git-rev-list command.
<args>...::
Flags and parameters to be parsed.
SPECIFYING REVISIONS
--------------------
A revision parameter typically, but not necessarily, names a
commit object. They use what is called an 'extended SHA1'
syntax. Here are various ways to spell object names. The
ones listed near the end of this list are to name trees and
blobs contained in a commit.
* The full SHA1 object name (40-byte hexadecimal string), or
a substring of such that is unique within the repository.
E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
name the same commit object if there are no other object in
your repository whose object name starts with dae86e.
* An output from `git-describe`; i.e. a closest tag, followed by a
dash, a `g`, and an abbreviated object name.
* A symbolic ref name. E.g. 'master' typically means the commit
object referenced by $GIT_DIR/refs/heads/master. If you
happen to have both heads/master and tags/master, you can
explicitly say 'heads/master' to tell git which one you mean.
When ambiguous, a `<name>` is disambiguated by taking the
first match in the following rules:
. if `$GIT_DIR/<name>` exists, that is what you mean (this is usually
useful only for `HEAD`, `FETCH_HEAD` and `MERGE_HEAD`);
. otherwise, `$GIT_DIR/refs/<name>` if exists;
. otherwise, `$GIT_DIR/refs/tags/<name>` if exists;
. otherwise, `$GIT_DIR/refs/heads/<name>` if exists;
. otherwise, `$GIT_DIR/refs/remotes/<name>` if exists;
. otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists.
* A ref followed by the suffix '@' with a date specification
enclosed in a brace
pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
of the ref at a prior point in time. This suffix may only be
used immediately following a ref name and the ref must have an
existing log ($GIT_DIR/logs/<ref>).
* A suffix '{caret}' to a revision parameter means the first parent of
that commit object. '{caret}<n>' means the <n>th parent (i.e.
'rev{caret}'
is equivalent to 'rev{caret}1'). As a special rule,
'rev{caret}0' means the commit itself and is used when 'rev' is the
object name of a tag object that refers to a commit object.
* A suffix '{tilde}<n>' to a revision parameter means the commit
object that is the <n>th generation grand-parent of the named
commit object, following only the first parent. I.e. rev~3 is
equivalent to rev{caret}{caret}{caret} which is equivalent to
rev{caret}1{caret}1{caret}1. See below for a illustration of
the usage of this form.
* A suffix '{caret}' followed by an object type name enclosed in
brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object
could be a tag, and dereference the tag recursively until an
object of that type is found or the object cannot be
dereferenced anymore (in which case, barf). `rev{caret}0`
introduced earlier is a short-hand for `rev{caret}\{commit\}`.
* A suffix '{caret}' followed by an empty brace pair
(e.g. `v0.99.8{caret}\{\}`) means the object could be a tag,
and dereference the tag recursively until a non-tag object is
found.
* A suffix ':' followed by a path; this names the blob or tree
at the given path in the tree-ish object named by the part
before the colon.
* A colon, optionally followed by a stage number (0 to 3) and a
colon, followed by a path; this names a blob object in the
index at the given path. Missing stage number (and the colon
that follows it) names an stage 0 entry.
Here is an illustration, by Jon Loeliger. Both node B and C are
a commit parents of commit node A. Parent commits are ordered
left-to-right.
G H I J
\ / \ /
D E F
\ | / \
\ | / |
\|/ |
B C
\ /
\ /
A
A = = A^0
B = A^ = A^1 = A~1
C = A^2 = A^2
D = A^^ = A^1^1 = A~2
E = B^2 = A^^2
F = B^3 = A^^3
G = A^^^ = A^1^1^1 = A~3
H = D^2 = B^^2 = A^^^2 = A~2^2
I = F^ = B^3^ = A^^3^
J = F^2 = B^3^2 = A^^3^2
SPECIFYING RANGES
-----------------
History traversing commands such as `git-log` operate on a set
of commits, not just a single commit. To these commands,
specifying a single revision with the notation described in the
previous section means the set of commits reachable from that
commit, following the commit ancestry chain.
To exclude commits reachable from a commit, a prefix `{caret}`
notation is used. E.g. "`{caret}r1 r2`" means commits reachable
from `r2` but exclude the ones reachable from `r1`.
This set operation appears so often that there is a shorthand
for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
the difference of two sets (subtract the set of commits
reachable from `r1` from the set of commits reachable from
`r2`).
A similar notation "`r1\...r2`" is called symmetric difference
of `r1` and `r2` and is defined as
"`r1 r2 --not $(git-merge-base --all r1 r2)`".
It it the set of commits that are reachable from either one of
`r1` or `r2` but not from both.
Two other shorthands for naming a set that is formed by a commit
and its parent commits exists. `r1{caret}@` notation means all
parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
its all parents.
Here are a handful examples:
D A B D
D F A B C D F
^A G B D
^A F B C F
G...I C D F G I
^B G I C D F G I
F^@ A B C
F^! H D F H
Author
------
Written by Linus Torvalds <torvalds@osdl.org> and
Junio C Hamano <junkio@cox.net>
Documentation
--------------
Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
GIT
---
Part of the gitlink:git[7] suite