GITREVISIONS(7)           (08/17/2021)            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
              The full SHA-1 object name (40-byte hexadecimal string),
              or a leading substring that is unique within the
              repository. E.g.
              dae86e1950b1277e545cee180551750029cfe735 and dae86e both
              name the same commit object if there is no other object
              in your repository whose object name starts with dae86e.

          <describeOutput>, e.g. v1.7.4.2-679-g3bee7fb
              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.

          <refname>, e.g. master, heads/master, refs/heads/master
              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

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              can explicitly say heads/master to tell Git which one
              you mean. When ambiguous, a <refname> is disambiguated
              by taking the first match in the following rules:

               1. If $GIT_DIR/<refname> exists, that is what you mean
                  (this is usually useful only for HEAD, FETCH_HEAD,
                  ORIG_HEAD, MERGE_HEAD and CHERRY_PICK_HEAD);

               2. otherwise, refs/<refname> if it exists;

               3. otherwise, refs/tags/<refname> if it exists;

               4. otherwise, refs/heads/<refname> if it exists;

               5. otherwise, refs/remotes/<refname> if it exists;

               6. otherwise, refs/remotes/<refname>/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 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.

          @
              @ alone is a shortcut for HEAD.

          [<refname>]@{<date>}, e.g. master@{yesterday}, HEAD@{5
          minutes ago}
              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}) specifies 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

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              and --until.

          <refname>@{<n>}, e.g. master@{1}
              A ref followed by the suffix @ with an ordinal
              specification enclosed in a brace pair (e.g.  {1}, {15})
              specifies 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/<refname>).

          @{<n>}, e.g. @{1}
              You can use the @ construct with an empty ref part to
              get at a reflog entry of the current branch. For
              example, if you are on branch blabla then @{1} means the
              same as blabla@{1}.

          @{-<n>}, e.g. @{-1}
              The construct @{-<n>} means the <n>th branch/commit
              checked out before the current one.

          [<branchname>]@{upstream}, e.g. master@{upstream}, @{u}
              The suffix @{upstream} to a branchname (short form
              <branchname>@{u}) refers to the branch that the branch
              specified by branchname is set to build on top of
              (configured with branch.<name>.remote and
              branch.<name>.merge). A missing branchname defaults to
              the current one. These suffixes are also accepted when
              spelled in uppercase, and they mean the same thing no
              matter the case.

          [<branchname>]@{push}, e.g. master@{push}, @{push}
              The suffix @{push} reports the branch "where we would
              push to" if git push were run while branchname was
              checked out (or the current HEAD if no branchname is
              specified). Since our push destination is in a remote
              repository, of course, we report the local tracking
              branch that corresponds to that branch (i.e., something
              in refs/remotes/).

              Herecqs 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

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              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
              A suffix ^ to a revision parameter 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.

          <rev>~[<n>], e.g. HEAD~, master~3
              A suffix ~ to a revision parameter means the first
              parent of that commit object. A suffix ~<n> to a
              revision parameter means the commit object that is the
              <n>th generation ancestor of the named commit object,
              following only the first parents. I.e.  <rev>~3 is
              equivalent to <rev>^^^ which is equivalent to
              <rev>^1^1^1. See below for an illustration of the usage
              of this form.

          <rev>^{<type>}, e.g. v0.99.8^{commit}
              A suffix ^ followed by an object type name enclosed in
              brace pair means dereference the object at <rev>
              recursively until an object of type <type> is found or
              the object cannot be dereferenced anymore (in which
              case, barf). For example, if <rev> is a commit-ish,
              <rev>^{commit} describes the corresponding commit
              object. Similarly, if <rev> is a tree-ish, <rev>^{tree}
              describes the corresponding tree object.  <rev>^0 is a
              short-hand for <rev>^{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^{}
              A suffix ^ followed by an empty brace pair means the
              object could be a tag, and dereference the tag
              recursively until a non-tag object is found.

          <rev>^{/<text>}, e.g. HEAD^{/fix nasty bug}

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              A suffix ^ to a revision parameter, followed by a brace
              pair that contains a text led by a slash, is the same as
              the :/fix nasty bug syntax below except that it returns
              the youngest matching commit which is reachable from the
              <rev> before ^.

          :/<text>, e.g. :/fix nasty bug
              A colon, followed by a slash, followed by a text, names
              a commit whose commit message matches the specified
              regular expression. This name returns the youngest
              matching commit which is reachable from any ref,
              including HEAD. The regular expression can match any
              part of the commit message. To match messages starting
              with a string, one can use e.g.  :/^foo. The special
              sequence :/!  is reserved for modifiers to what is
              matched.  :/!-foo performs a negative match, while
              :/!!foo matches a literal !  character, followed by foo.
              Any other sequence beginning with :/!  is reserved for
              now. Depending on the given text, the shellcqs word
              splitting rules might require additional quoting.

          <rev>:<path>, e.g. HEAD:README, master:./README
              A suffix : followed by a path names the blob or tree at
              the given path in the tree-ish object named by the part
              before 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
              treecqs root directory. This is most useful to address a
              blob or tree from a commit or tree that has the same
              tree structure as the working tree.

          :[<n>:]<path>, e.g. :0:README, :README
              A colon, optionally followed by a stage number (0 to 3)
              and a colon, followed by a path, names a blob object in
              the index at the given path. A missing stage number (and
              the colon that follows it) names a stage 0 entry. During
              a merge, stage 1 is the common ancestor, stage 2 is the
              target branchcqs version (typically the current branch),
              and stage 3 is the version from the branch which is
              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

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                     \   /
                      \ /
                       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 commitcqs 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
              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 (i.e.  r1
              and its ancestors).

        Dotted Range Notations
          The .. (two-dot) Range Notation
              The ^r1 r2 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.

          The ... (three-dot) Symmetric Difference Notation
              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

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              that are reachable from either one of r1 (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 "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

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          you can say HEAD^2^@, however you cannot say HEAD^@^2.

     REVISION RANGE SUMMARY
          <rev>
              Include commits that are reachable from <rev> (i.e.
              <rev> and its ancestors).

          ^<rev>
              Exclude commits that are reachable from <rev> (i.e.
              <rev> and its ancestors).

          <rev1>..<rev2>
              Include commits that are reachable from <rev2> but
              exclude those that are reachable from <rev1>. When
              either <rev1> or <rev2> is omitted, it defaults to HEAD.

          <rev1>...<rev2>
              Include commits that are reachable from either <rev1> or
              <rev2> but exclude those that are reachable from both.
              When either <rev1> or <rev2> is omitted, it defaults to
              HEAD.

          <rev>^@, e.g. HEAD^@
              A suffix ^ followed by an at sign is the same as listing
              all parents of <rev> (meaning, include anything
              reachable from its parents, but not the commit itself).

          <rev>^!, e.g. HEAD^!
              A suffix ^ followed by an exclamation mark is the same
              as giving commit <rev> and then all its parents prefixed
              with ^ to exclude them (and their ancestors).

          <rev>^-<n>, e.g. HEAD^-, HEAD^-2
              Equivalent to <rev>^<n>..<rev>, with <n> = 1 if not
              given.

          Here are a handful of examples using the Loeliger
          illustration above, with each step in the notationcqs
          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

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                        = 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-rev-parse(1)

     GIT
          Part of the git(1) suite

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