GITREVISIONS(7) Git Manual GITREVISIONS(7)NAMEgitrevisions - specifying revisions and ranges for git
SYNOPSISgitrevisionsDESCRIPTION
Many Git commands take revision parameters as arguments. Depending on
the command, they denote a specific commit or, for commands which walk
the revision graph (such as git-log(1)), all commits which can be
reached from that commit. In the latter case one can also specify a
range of revisions explicitly.
In addition, some Git commands (such as git-show(1)) also take revision
parameters which denote other objects than commits, e.g. blobs
("files") or trees ("directories of files").
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, optionally
followed by a dash and a number of commits, 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 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:
1. if $GIT_DIR/<name> exists, that is what you mean (this is
usually useful only for HEAD, FETCH_HEAD, ORIG_HEAD and
MERGE_HEAD);
2. otherwise, refs/<name> if exists;
3. otherwise, refs/tags/<name> if exists;
4. otherwise, refs/heads/<name> if exists;
5. otherwise, refs/remotes/<name> if exists;
6. otherwise, refs/remotes/<name>/HEAD if exists.
HEAD names the commit your changes in the working tree is based
on. FETCH_HEAD records the branch you fetched from a remote
repository with your last git fetch invocation. ORIG_HEAD is
created by commands that moves your HEAD in a drastic way, to
record the position of the HEAD before their operation, so that
you can change the tip of the branch back to the state before
you ran them easily. MERGE_HEAD records the commit(s) you are
merging into your branch when you run git merge.
Note that any of the refs/* cases above may come either from
the $GIT_DIR/refs directory or from the $GIT_DIR/packed-refs
file.
· A ref followed by the suffix @ with a date specification enclosed
in a brace pair (e.g. {yesterday}, {1 month 2 weeks 3 days 1 hour
1 second ago} or {1979-02-26 18:30:00}) to specify the value of the
ref at a prior point in time. This suffix may only be used
immediately following a ref name and the ref must have an existing
log ($GIT_DIR/logs/<ref>). Note that this looks up the state of
your local ref at a given time; e.g., what was in your local master
branch last week. If you want to look at commits made during
certain times, see --since and --until.
· A ref followed by the suffix @ with an ordinal specification
enclosed in a brace pair (e.g. {1}, {15}) to specify the n-th
prior value of that ref. For example master@{1} is the immediate
prior value of master while master@{5} is the 5th prior value of
master. This suffix may only be used immediately following a ref
name and the ref must have an existing log ($GIT_DIR/logs/<ref>).
· You can use the @ construct with an empty ref part to get at a
reflog of the current branch. For example, if you are on the branch
blabla, then @{1} means the same as blabla@{1}.
· The special construct @{-<n>} means the <n>th branch checked out
before the current one.
· The suffix @{upstream} to a ref (short form ref@{u}) refers to the
branch the ref is set to build on top of. Missing ref defaults to
the current branch.
· A suffix ^ to a revision parameter (e.g. HEAD^) means the first
parent of that commit object. ^<n> means the <n>th parent (i.e.
rev^ is equivalent to rev^1). As a special rule, rev^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 ~<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^^^
which is equivalent to rev^1^1^1. See below for a illustration of
the usage of this form.
· A suffix ^ followed by an object type name enclosed in brace pair
(e.g. v0.99.8^{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^0 introduced earlier is a short-hand for rev^{commit}.
· A suffix ^ followed by an empty brace pair (e.g. v0.99.8^{}) means
the object could be a tag, and dereference the tag recursively
until a non-tag object is found.
· A suffix ^ to a revision parameter followed by a brace pair that
contains a text led by a slash (e.g. HEAD^{/fix nasty bug}): this
is the same as :/fix nasty bug syntax below except that it returns
the youngest matching commit which is reachable from the ref before
^.
· A colon, followed by a slash, followed by a text (e.g. :/fix nasty
bug): this names a commit whose commit message matches the
specified regular expression. This name returns the youngest
matching commit which is reachable from any ref. If the commit
message starts with a !, you have to repeat that; the special
sequence :/!, followed by something else than ! is reserved for
now. The regular expression can match any part of the commit
message. To match messages starting with a string, one can use e.g.
:/^foo.
· A suffix : followed by a path (e.g. HEAD:README); this names the
blob or tree at the given path in the tree-ish object named by the
part before the colon. :path (with an empty part before the colon,
e.g. :README) is a special case of the syntax described next:
content recorded in the index at the given path. A path starting
with ./ or ../ is relative to current working directory. The given
path will be converted to be relative to working tree’s root
directory. This is most useful to address a blob or tree from a
commit or tree that has the same tree structure with the working
tree.
· A colon, optionally followed by a stage number (0 to 3) and a
colon, followed by a path (e.g. :0:README); this names a blob
object in the index at the given path. Missing stage number (and
the colon that follows it, e.g. :README) names a stage 0 entry.
During a merge, stage 1 is the common ancestor, stage 2 is the
target branch’s version (typically the current branch), and stage 3
is the version from the branch being merged.
Here is an illustration, by Jon Loeliger. Both commit nodes B and C are
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 ^ notation is
used. E.g. ^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.
When you have two commits r1 and r2 (named according to the syntax
explained in SPECIFYING REVISIONS above), you can ask for commits that
are reachable from r2 excluding those that are reachable from r1 by ^r1
r2 and it can be written as r1..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 is 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 exist. The r1^@ notation means all parents of r1.
r1^! includes commit r1 but excludes all of its parents.
Here are a handful of examples:
D G H D
D F G H I J D F
^G D H D
^D B E I J F B
B...C G H D E B C
^D B C E I J F B C
C^@ I J F
F^! D G H D F
SEE ALSOgit-rev-parse(1)GIT
Part of the git(1) suite
Git 1.7.4.1 04/26/2011 GITREVISIONS(7)
