NAME

gitrevisions - Specifying revisions and ranges for Git

SYNOPSIS

gitrevisions

DESCRIPTION

Many Git commands take revision parameters as arguments. Depending onthe command, they denote a specific commit or, for commands whichwalk the revision graph (such as git-log[1]), all commits which arereachable from that commit. For commands that walk the revision graph one canalso specify a range of revisions explicitly.

In addition, some Git commands (such as git-show[1] andgit-push[1]) can also take revision parameters which denoteother objects than commits, e.g. blobs ("files") or trees("directories of files").

SPECIFYING REVISIONS

A revision parameter <rev> typically, but not necessarily, names acommit object. It uses what is called an _extended SHA-1_syntax. Here are various ways to spell object names. Theones listed near the end of this list name trees andblobs contained in a commit.

NoteThis document shows the "raw" syntax as seen by git. The shelland other UIs might require additional quoting to protect specialcharacters and to avoid word splitting.
  • , e.g. dae86e1950b1277e545cee180551750029cfe735, dae86e

  • The full SHA-1 object name (40-byte hexadecimal string), ora leading substring that is unique within the repository.E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e bothname the same commit object if there is no other object inyour repository whose object name starts with dae86e.

  • , e.g. v1.7.4.2-679-g3bee7fb

  • Output from git describe; i.e. a closest tag, optionallyfollowed by a dash and a number of commits, followed by a dash, ag, and an abbreviated object name.

  • , e.g. master, heads/master, refs/heads/master

  • A symbolic ref name. E.g. master typically means the commitobject referenced by refs/heads/master. If youhappen to have both heads/master and tags/master, you canexplicitly say heads/master to tell Git which one you mean.When ambiguous, a is disambiguated by taking thefirst match in the following rules:

  • If $GIT_DIR/ exists, that is what you mean (this is usuallyuseful only for HEAD, FETCH_HEAD, ORIG_HEAD, MERGE_HEADand CHERRY_PICK_HEAD);

  • otherwise, refs/ if it exists;

  • otherwise, refs/tags/ if it exists;

  • otherwise, refs/heads/ if it exists;

  • otherwise, refs/remotes/ if it exists;

  • otherwise, refs/remotes//HEAD if it exists.

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 repositorywith your last git fetch invocation.ORIG_HEAD is created by commands that move your HEAD in a drasticway, to record the position of the HEAD before their operation, so thatyou can easily change the tip of the branch back to the state before you ranthem.MERGE_HEAD records the commit(s) which you are merging into your branchwhen you run git merge.CHERRY_PICK_HEAD records the commit which you are cherry-pickingwhen you run git cherry-pick.

Note that any of the refs/* cases above may come either fromthe $GIT_DIR/refs directory or from the $GIT_DIR/packed-refs file.While the ref name encoding is unspecified, UTF-8 is preferred assome output processing may assume ref names in UTF-8.

  • @

  • @ alone is a shortcut for HEAD.

  • []@{}, e.g. master@{yesterday}, HEAD@{5 minutes ago}

  • A ref followed by the suffix @ with a date specificationenclosed in a bracepair (e.g. {yesterday}, {1 month 2 weeks 3 days 1 hour 1second ago} or {1979-02-26 18:30:00}) specifies the valueof the ref at a prior point in time. This suffix may only beused immediately following a ref name and the ref must have anexisting log ($GIT_DIR/logs/). Note that this looks up the stateof your local ref at a given time; e.g., what was in your localmaster branch last week. If you want to look at commits made duringcertain times, see —since and —until.

  • @{}, e.g. master@{1}

  • A ref followed by the suffix @ with an ordinal specificationenclosed in a brace pair (e.g. {1}, {15}) specifiesthe 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 usedimmediately following a ref name and the ref must have an existinglog ($GIT_DIR/logs/).

  • @{}, e.g. @{1}

  • You can use the @ construct with an empty ref part to get at areflog entry of the current branch. For example, if you are onbranch blabla then @{1} means the same as blabla@{1}.

  • @{-}, e.g. @{-1}

  • The construct @{-} means the th branch/commit checked outbefore the current one.

  • []@{upstream}, e.g. master@{upstream}, @{u}

  • The suffix @{upstream} to a branchname (short form @{u})refers to the branch that the branch specified by branchname is set to build ontop of (configured with branch.<name>.remote andbranch.<name>.merge). A missing branchname defaults to thecurrent one. These suffixes are also accepted when spelled in uppercase, andthey mean the same thing no matter the case.

  • []@{push}, e.g. master@{push}, @{push}

  • The suffix @{push} reports the branch "where we would push to" ifgit push were run while branchname was checked out (or the currentHEAD if no branchname is specified). Since our push destination isin a remote repository, of course, we report the local tracking branchthat corresponds to that branch (i.e., something in refs/remotes/).

Here’s an example to make it more clear:

  1. $ git config push.default current
  2. $ git config remote.pushdefault myfork
  3. $ git switch -c mybranch origin/master
  4.  
  5. $ git rev-parse --symbolic-full-name @{upstream}
  6. refs/remotes/origin/master
  7.  
  8. $ git rev-parse --symbolic-full-name @{push}
  9. refs/remotes/myfork/mybranch

Note in the example that we set up a triangular workflow, where we pullfrom 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 samething no matter the case.

  • ^[], e.g. HEAD^, v1.5.1^0

  • A suffix ^ to a revision parameter means the first parent ofthat commit object. ^ means the th parent (i.e.^_is equivalent to ^1). As a special rule,^0 means the commit itself and is used when _ is theobject name of a tag object that refers to a commit object.

  • ~[], e.g. HEAD~, master~3

  • A suffix ~ to a revision parameter means the first parent ofthat commit object.A suffix ~ to a revision parameter means the commitobject that is the th generation ancestor of the namedcommit object, following only the first parents. I.e. ~3 isequivalent to ^^^ which is equivalent to^1^1^1. See below for an illustration ofthe usage of this form.

  • ^{}, e.g. v0.99.8^{commit}

  • A suffix ^ followed by an object type name enclosed inbrace pair means dereference the object at recursively untilan object of type is found or the object cannot bedereferenced anymore (in which case, barf).For example, if is a commit-ish, ^{commit}_describes the corresponding commit object.Similarly, if is a tree-ish, ^{tree}describes the corresponding tree object.^0is a short-hand for ^{commit}_.

^{object} can be used to make sure names anobject that exists, without requiring to be a tag, andwithout dereferencing ; because a tag is already an object,it does not have to be dereferenced even once to get to an object.

^{tag} can be used to ensure that identifies anexisting tag object.

  • ^{}, e.g. v0.99.8^{}

  • A suffix ^ followed by an empty brace pairmeans the object could be a tag,and dereference the tag recursively until a non-tag object isfound.

  • ^{/}, e.g. HEAD^{/fix nasty bug}

  • A suffix ^ to a revision parameter, followed by a bracepair that contains a text led by a slash,is the same as the :/fix nasty bug syntax below except thatit returns the youngest matching commit which is reachable fromthe before ^.

  • :/, e.g. :/fix nasty bug

  • A colon, followed by a slash, followed by a text, namesa commit whose commit message matches the specified regular expression.This name returns the youngest matching commit which isreachable from any ref, including HEAD.The regular expression can match any part of thecommit message. To match messages starting with a string, one can usee.g. :/^foo. The special sequence :/! is reserved for modifiers to whatis matched. :/!-foo performs a negative match, while :/!!foo matches aliteral ! character, followed by foo. Any other sequence beginning with:/! is reserved for now.Depending on the given text, the shell’s word splitting rules mightrequire additional quoting.

  • :, e.g. HEAD:README, master:./README

  • A suffix : followed by a path names the blob or treeat the given path in the tree-ish object named by the partbefore the colon.A path starting with ./ or ../ is relative to the current working directory.The given path will be converted to be relative to the working tree’s root directory.This is most useful to address a blob or tree from a commit or tree that hasthe same tree structure as the working tree.

  • :[:], e.g. :0:README, :README

  • A colon, optionally followed by a stage number (0 to 3) and acolon, followed by a path, names a blob object in theindex at the given path. A missing stage number (and the colonthat follows it) names a stage 0 entry. During a merge, stage1 is the common ancestor, stage 2 is the target branch’s version(typically the current branch), and stage 3 is the version fromthe branch which is being merged.

Here is an illustration, by Jon Loeliger. Both commit nodes Band C are parents of commit node A. Parent commits are orderedleft-to-right.

  1. G   H   I   J
  2.  \ /     \ /
  3.   D   E   F
  4.    \  |  / \
  5.     \ | /   |
  6.      \|/    |
  7.       B     C
  8.        \   /
  9.         \ /
  10.          A
  1. A =      = A^0
  2. B = A^   = A^1     = A~1
  3. C = A^2  = A^2
  4. D = A^^  = A^1^1   = A~2
  5. E = B^2  = A^^2
  6. F = B^3  = A^^3
  7. G = A^^^ = A^1^1^1 = A~3
  8. H = D^2  = B^^2    = A^^^2  = A~2^2
  9. I = F^   = B^3^    = A^^3^
  10. J = F^2  = B^3^2   = A^^3^2

SPECIFYING RANGES

History traversing commands such as git log operate on a setof commits, not just a single commit.

For these commands,specifying a single revision, using the notation described in theprevious section, means the set of commits reachable from the givencommit.

A commit’s reachable set is the commit itself and the commits inits ancestry chain.

Commit Exclusions

  • ^ (caret) Notation
  • To exclude commits reachable from a commit, a prefix ^_notation is used. E.g. ^r1 r2 means commits reachablefrom _r2 but exclude the ones reachable from r1 (i.e. r1 andits ancestors).

Dotted Range Notations

  • The .. (two-dot) Range Notation

  • The ^r1 r2 set operation appears so often that there is a shorthandfor it. When you have two commits r1 and r2 (named accordingto the syntax explained in SPECIFYING REVISIONS above), you can askfor commits that are reachable from r2 excluding those that are reachablefrom r1 by ^r1 r2 and it can be written as r1..r2.

  • The …​ (three-dot) Symmetric Difference Notation

  • A similar notation r1…r2 is called symmetric differenceof r1 and r2 and is defined asr1 r2 —not $(git merge-base —all r1 r2).It is the set of commits that are reachable from either one ofr1 (left side) or r2 (right side) but not from both.

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 "Whatdid I do since I forked from the origin branch?" Similarly, ..origin_is a shorthand for _HEAD..origin and asks "What did the origin do sinceI forked from them?" Note that .. would mean HEAD..HEAD which is anempty range that is both reachable and unreachable from HEAD.

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>thparent (i.e. a shorthand for <rev>^<n>..<rev>), with <n> = 1 ifnot given. This is typically useful for merge commits where youcan just pass <commit>^- to get all the commits in the branchthat was merged in merge commit <commit> (including _<commit>_itself).

While <rev>^<n> was about specifying a single commit parent, thesethree notations also consider its parents. For example you can sayHEAD^2^@, however you cannot say HEAD^@^2.

Revision Range Summary

  • Include commits that are reachable from (i.e. and itsancestors).

  • ^

  • Exclude commits that are reachable from (i.e. and itsancestors).

  • ..

  • Include commits that are reachable from but excludethose that are reachable from . When either or is omitted, it defaults to HEAD.

  • …

  • Include commits that are reachable from either or but exclude those that are reachable from both. Wheneither or is omitted, it defaults to HEAD.

  • ^@, e.g. HEAD^@

  • A suffix ^ followed by an at sign is the same as listingall parents of (meaning, include anything reachable fromits parents, but not the commit itself).

  • ^!, e.g. HEAD^!

  • A suffix ^ followed by an exclamation mark is the sameas giving commit and then all its parents prefixed with^ to exclude them (and their ancestors).

  • ^-, e.g. HEAD^-, HEAD^-2

  • Equivalent to ^.., with = 1 if notgiven.

Here are a handful of examples using the Loeliger illustration above,with each step in the notation’s expansion and selection carefullyspelt out:

  1.    Args   Expanded arguments    Selected commits
  2.    D                            G H D
  3.    D F                          G H I J D F
  4.    ^G D                         H D
  5.    ^D B                         E I J F B
  6.    ^D B C                       E I J F B C
  7.    C                            I J F C
  8.    B..C   = ^B C                C
  9.    B...C  = B ^F C              G H D E B C
  10.    B^-    = B^..B
  11.       = ^B^1 B              E I J F B
  12.    C^@    = C^1
  13.       = F                   I J F
  14.    B^@    = B^1 B^2 B^3
  15.       = D E F               D G H E F I J
  16.    C^!    = C ^C^@
  17.       = C ^C^1
  18.       = C ^F                C
  19.    B^!    = B ^B^@
  20.       = B ^B^1 ^B^2 ^B^3
  21.       = B ^D ^E ^F          B
  22.    F^! D  = F ^I ^J D           G H D F

SEE ALSO

git-rev-parse[1]

GIT

Part of the git[1] suite