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GITREVISIONS(7) | Git Manual | GITREVISIONS(7) |
NAME¶
gitrevisions - Specifying revisions and ranges for Git
SYNOPSIS¶
gitrevisions
DESCRIPTION¶
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 are reachable from that commit. For commands that walk the revision graph one can also specify a range of revisions explicitly.
In addition, some Git commands (such as git-show(1) and git-push(1)) can also take revision parameters which denote other objects than commits, e.g. blobs ("files") or trees ("directories of files").
SPECIFYING REVISIONS¶
A revision parameter <rev> typically, but not necessarily, names a commit object. It uses what is called an extended SHA-1 syntax. Here are various ways to spell object names. The ones listed near the end of this list name trees and blobs contained in a commit.
Note
This document shows the "raw" syntax as seen by git. The shell and other UIs might require additional quoting to protect special characters and to avoid word splitting.
<sha1>, e.g. dae86e1950b1277e545cee180551750029cfe735, dae86e
<describeOutput>, e.g. v1.7.4.2-679-g3bee7fb
<refname>, e.g. master, heads/master, refs/heads/master
HEAD names the commit on which you based the changes in the working tree. FETCH_HEAD records the branch which you fetched from a remote repository with your last git fetch invocation. ORIG_HEAD is created by commands that move your HEAD in a drastic way, to record the position of the HEAD before their operation, so that you can easily change the tip of the branch back to the state before you ran them. MERGE_HEAD records the commit(s) which you are merging into your branch when you run git merge. CHERRY_PICK_HEAD records the commit which you are cherry-picking when you run git cherry-pick.
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. While the ref name encoding is unspecified, UTF-8 is preferred as some output processing may assume ref names in UTF-8.
@
[<refname>]@{<date>}, e.g. master@{yesterday}, HEAD@{5 minutes ago}
<refname>@{<n>}, e.g. master@{1}
@{<n>}, e.g. @{1}
@{-<n>}, e.g. @{-1}
[<branchname>]@{upstream}, e.g. master@{upstream}, @{u}
[<branchname>]@{push}, e.g. master@{push}, @{push}
Here’s an example to make it more clear:
$ git config push.default current $ git config remote.pushdefault myfork $ git switch -c mybranch origin/master $ git rev-parse --symbolic-full-name @{upstream} refs/remotes/origin/master $ git rev-parse --symbolic-full-name @{push} refs/remotes/myfork/mybranch
Note in the example that we set up a triangular workflow, where we pull from one location and push to another. In a non-triangular workflow, @{push} is the same as @{upstream}, and there is no need for it.
This suffix is also accepted when spelled in uppercase, and means the same thing no matter the case.
<rev>^[<n>], e.g. HEAD^, v1.5.1^0
<rev>~[<n>], e.g. HEAD~, master~3
<rev>^{<type>}, e.g. v0.99.8^{commit}
<rev>^{object} can be used to make sure <rev> names an object that exists, without requiring <rev> to be a tag, and without dereferencing <rev>; because a tag is already an object, it does not have to be dereferenced even once to get to an object.
<rev>^{tag} can be used to ensure that <rev> identifies an existing tag object.
<rev>^{}, e.g. v0.99.8^{}
<rev>^{/<text>}, e.g. HEAD^{/fix nasty bug}
:/<text>, e.g. :/fix nasty bug
<rev>:<path>, e.g. HEAD:README, master:./README
:[<n>:]<path>, e.g. :0:README, :README
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 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.
For these commands, specifying a single revision, using the notation described in the previous section, means the set of commits reachable from the given commit.
Specifying several revisions means the set of commits reachable from any of the given commits.
A commit’s reachable set is the commit itself and the commits in its ancestry chain.
There are several notations to specify a set of connected commits (called a "revision range"), illustrated below.
Commit Exclusions¶
^<rev> (caret) Notation
Dotted Range Notations¶
The .. (two-dot) Range Notation
The ... (three-dot) Symmetric Difference Notation
In these two shorthand notations, you can omit one end and let it default to HEAD. For example, origin.. is a shorthand for origin..HEAD and asks "What did I do since I forked from the origin branch?" Similarly, ..origin is a shorthand for HEAD..origin and asks "What did the origin do since I forked from them?" Note that .. would mean HEAD..HEAD which is an empty range that is both reachable and unreachable from HEAD.
Commands that are specifically designed to take two distinct ranges (e.g. "git range-diff R1 R2" to compare two ranges) do exist, but they are exceptions. Unless otherwise noted, all "git" commands that operate on a set of commits work on a single revision range. In other words, writing two "two-dot range notation" next to each other, e.g.
$ git log A..B C..D
does not specify two revision ranges for most commands. Instead it will name a single connected set of commits, i.e. those that are reachable from either B or D but are reachable from neither A or C. In a linear history like this:
---A---B---o---o---C---D
because A and B are reachable from C, the revision range specified by these two dotted ranges is a single commit D.
Other <rev>^ Parent Shorthand Notations¶
Three other shorthands exist, particularly useful for merge commits, for naming a set that is formed by a commit and its parent commits.
The r1^@ notation means all parents of r1.
The r1^! notation includes commit r1 but excludes all of its parents. By itself, this notation denotes the single commit r1.
The <rev>^-[<n>] notation includes <rev> but excludes the <n>th parent (i.e. a shorthand for <rev>^<n>..<rev>), with <n> = 1 if not given. This is typically useful for merge commits where you can just pass <commit>^- to get all the commits in the branch that was merged in merge commit <commit> (including <commit> itself).
While <rev>^<n> was about specifying a single commit parent, these three notations also consider its parents. For example you can say HEAD^2^@, however you cannot say HEAD^@^2.
REVISION RANGE SUMMARY¶
<rev>
^<rev>
<rev1>..<rev2>
<rev1>...<rev2>
<rev>^@, e.g. HEAD^@
<rev>^!, e.g. HEAD^!
<rev>^-<n>, e.g. HEAD^-, HEAD^-2
Here are a handful of examples using the Loeliger illustration above, with each step in the notation’s expansion and selection carefully spelt out:
Args Expanded arguments Selected commits
D G H D
D F G H I J D F
^G D H D
^D B E I J F B
^D B C E I J F B C
C I J F C
B..C = ^B C C
B...C = B ^F C G H D E B C
B^- = B^..B
= ^B^1 B E I J F B
C^@ = C^1
= F I J F
B^@ = B^1 B^2 B^3
= D E F D G H E F I J
C^! = C ^C^@
= C ^C^1
= C ^F C
B^! = B ^B^@
= B ^B^1 ^B^2 ^B^3
= B ^D ^E ^F B
F^! D = F ^I ^J D G H D F
SEE ALSO¶
GIT¶
Part of the git(1) suite
02/14/2022 | Git 2.35.1 |