NAME

git-rev-parse - Pick out and massage parameters

SYNOPSIS

  1. git rev-parse [<options>] <args>…​

DESCRIPTION

Many Git porcelainish commands take mixture of flags(i.e. parameters that begin with a dash -) and parametersmeant for the underlying git rev-list command they use internallyand flags and parameters for the other commands they usedownstream of git rev-list. This command is used todistinguish between them.

OPTIONS

Operation Modes

Each of these options must appear first on the command line.

  • —parseopt

  • Use git rev-parse in option parsing mode (see PARSEOPT section below).

  • —sq-quote

  • Use git rev-parse in shell quoting mode (see SQ-QUOTEsection below). In contrast to the —sq option below, thismode does only quoting. Nothing else is done to command input.

Options for —parseopt

  • —keep-dashdash

  • Only meaningful in —parseopt mode. Tells the option parser to echoout the first — met instead of skipping it.

  • —stop-at-non-option

  • Only meaningful in —parseopt mode. Lets the option parser stop atthe first non-option argument. This can be used to parse sub-commandsthat take options themselves.

  • —stuck-long

  • Only meaningful in —parseopt mode. Output the options in theirlong form if available, and with their arguments stuck.

Options for Filtering

  • —revs-only

  • Do not output flags and parameters not meant forgit rev-list command.

  • —no-revs

  • Do not output flags and parameters meant forgit rev-list command.

  • —flags

  • Do not output non-flag parameters.

  • —no-flags

  • Do not output flag parameters.

Options for Output

  • —default

  • If there is no parameter given by the user, use <arg>instead.

  • —prefix

  • Behave as if git rev-parse was invoked from the <arg>subdirectory of the working tree. Any relative filenames areresolved as if they are prefixed by <arg> and will be printedin that form.

This can be used to convert arguments to a command run in a subdirectoryso that they can still be used after moving to the top-level of therepository. For example:

  1. prefix=$(git rev-parse --show-prefix)
  2. cd "$(git rev-parse --show-toplevel)"
  3. # rev-parse provides the -- needed for 'set'
  4. eval "set $(git rev-parse --sq --prefix "$prefix" -- "$@")"
  • —verify
  • Verify that exactly one parameter is provided, and that itcan be turned into a raw 20-byte SHA-1 that can be used toaccess the object database. If so, emit it to the standardoutput; otherwise, error out.

If you want to make sure that the output actually names an object inyour object database and/or can be used as a specific type of objectyou require, you can add the ^{type} peeling operator to the parameter.For example, git rev-parse "$VAR^{commit}" will make sure $VARnames an existing object that is a commit-ish (i.e. a commit, or anannotated tag that points at a commit). To make sure that $VARnames an existing object of any type, git rev-parse "$VAR^{object}"can be used.

  • -q
  • —quiet

  • Only meaningful in —verify mode. Do not output an errormessage if the first argument is not a valid object name;instead exit with non-zero status silently.SHA-1s for valid object names are printed to stdout on success.

  • —sq

  • Usually the output is made one line per flag andparameter. This option makes output a single line,properly quoted for consumption by shell. Useful whenyou expect your parameter to contain whitespaces andnewlines (e.g. when using pickaxe -S withgit diff-*). In contrast to the —sq-quote option,the command input is still interpreted as usual.

  • —short[=length]

  • Same as —verify but shortens the object name to a uniqueprefix with at least length characters. The minimum lengthis 4, the default is the effective value of the core.abbrevconfiguration variable (see git-config[1]).

  • —not

  • When showing object names, prefix them with ^ andstrip ^ prefix from the object names that already haveone.

  • —abbrev-ref[=(strict|loose)]

  • A non-ambiguous short name of the objects name.The option core.warnAmbiguousRefs is used to select the strictabbreviation mode.

  • —symbolic

  • Usually the object names are output in SHA-1 form (withpossible ^ prefix); this option makes them output in aform as close to the original input as possible.

  • —symbolic-full-name

  • This is similar to —symbolic, but it omits input thatare not refs (i.e. branch or tag names; or moreexplicitly disambiguating "heads/master" form, when youwant to name the "master" branch when there is anunfortunately named tag "master"), and show them as fullrefnames (e.g. "refs/heads/master").

Options for Objects

  • —all

  • Show all refs found in refs/.

  • —branches[=pattern]

  • —tags[=pattern]
  • —remotes[=pattern]
  • Show all branches, tags, or remote-tracking branches,respectively (i.e., refs found in refs/heads,refs/tags, or refs/remotes, respectively).

If a pattern is given, only refs matching the given shell glob areshown. If the pattern does not contain a globbing character (?,, or [), it is turned into a prefix match by appending /.

  • —glob=pattern

  • Show all refs matching the shell glob pattern pattern. Ifthe pattern does not start with refs/, this is automaticallyprepended. If the pattern does not contain a globbingcharacter (?, , or [), it is turned into a prefixmatch by appending /.

  • —exclude=

  • Do not include refs matching that the next —all,—branches, —tags, —remotes, or —glob would otherwiseconsider. Repetitions of this option accumulate exclusion patternsup to the next —all, —branches, —tags, —remotes, or—glob option (other options or arguments do not clearaccumulated patterns).

The patterns given should not begin with refs/heads, refs/tags, orrefs/remotes when applied to —branches, —tags, or —remotes,respectively, and they must begin with refs/ when applied to —globor —all. If a trailing /* is intended, it must be givenexplicitly.

  • —disambiguate=
  • Show every object whose name begins with the given prefix.The must be at least 4 hexadecimal digits long toavoid listing each and every object in the repository bymistake.

Options for Files

  • —local-env-vars

  • List the GIT_* environment variables that are local to therepository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).Only the names of the variables are listed, not their value,even if they are set.

  • —git-dir

  • Show $GIT_DIR if defined. Otherwise show the path tothe .git directory. The path shown, when relative, isrelative to the current working directory.

If $GIT_DIR is not defined and the current directoryis not detected to lie in a Git repository or work treeprint a message to stderr and exit with nonzero status.

  • —absolute-git-dir

  • Like —git-dir, but its output is always the canonicalizedabsolute path.

  • —git-common-dir

  • Show $GIT_COMMON_DIR if defined, else $GIT_DIR.

  • —is-inside-git-dir

  • When the current working directory is below the repositorydirectory print "true", otherwise "false".

  • —is-inside-work-tree

  • When the current working directory is inside the work tree of therepository print "true", otherwise "false".

  • —is-bare-repository

  • When the repository is bare print "true", otherwise "false".

  • —is-shallow-repository

  • When the repository is shallow print "true", otherwise "false".

  • —resolve-git-dir

  • Check if is a valid repository or a gitfile thatpoints at a valid repository, and print the location of therepository. If is a gitfile then the resolved pathto the real repository is printed.

  • —git-path

  • Resolve "$GIT_DIR/" and takes other path relocationvariables such as $GIT_OBJECT_DIRECTORY,$GIT_INDEX_FILE…​ into account. For example, if$GIT_OBJECT_DIRECTORY is set to /foo/bar then "git rev-parse—git-path objects/abc" returns /foo/bar/abc.

  • —show-cdup

  • When the command is invoked from a subdirectory, show thepath of the top-level directory relative to the currentdirectory (typically a sequence of "../", or an empty string).

  • —show-prefix

  • When the command is invoked from a subdirectory, show thepath of the current directory relative to the top-leveldirectory.

  • —show-toplevel

  • Show the absolute path of the top-level directory.

  • —show-superproject-working-tree

  • Show the absolute path of the root of the superproject’sworking tree (if exists) that uses the current repository asits submodule. Outputs nothing if the current repository isnot used as a submodule by any project.

  • —shared-index-path

  • Show the path to the shared index file in split index mode, orempty if not in split-index mode.

Other Options

  • —since=datestring
  • —after=datestring

  • Parse the date string, and output the corresponding—max-age= parameter for git rev-list.

  • —until=datestring

  • —before=datestring

  • Parse the date string, and output the corresponding—min-age= parameter for git rev-list.

  • …​

  • Flags and parameters to be parsed.

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

PARSEOPT

In —parseopt mode, git rev-parse helps massaging options to bring to shellscripts the same facilities C builtins have. It works as an option normalizer(e.g. splits single switches aggregate values), a bit like getopt(1) does.

It takes on the standard input the specification of the options to parse andunderstand, and echoes on the standard output a string suitable for sh(1) evalto replace the arguments with normalized ones. In case of error, it outputsusage on the standard error stream, and exits with code 129.

Note: Make sure you quote the result when passing it to eval. Seebelow for an example.

Input Format

git rev-parse —parseopt input format is fully text based. It has two parts,separated by a line that contains only —. The lines before the separator(should be one or more) are used for the usage.The lines after the separator describe the options.

Each line of options has this format:

  1. <opt-spec><flags>*<arg-hint>? SP+ help LF
  • <opt-spec>

  • its format is the short option character, then the long option nameseparated by a comma. Both parts are not required, though at least oneis necessary. May not contain any of the <flags> characters.h,help, dry-run and f are examples of correct <opt-spec>.

  • <flags>

  • <flags> are of *, =, ? or !.

  • Use = if the option takes an argument.

  • Use ? to mean that the option takes an optional argument. Youprobably want to use the —stuck-long mode to be able tounambiguously parse the optional argument.

  • Use * to mean that this option should not be listed in the usagegenerated for the -h argument. It’s shown for —help-all asdocumented in gitcli[7].

  • Use ! to not make the corresponding negated long option available.

  • <arg-hint>
  • <arg-hint>, if specified, is used as a name of the argument in thehelp output, for options that take arguments. <arg-hint> isterminated by the first whitespace. It is customary to use adash to separate words in a multi-word argument hint.

The remainder of the line, after stripping the spaces, is usedas the help associated to the option.

Blank lines are ignored, and lines that don’t match this specification are usedas option group headers (start the line with a space to create suchlines on purpose).

Example

  1. OPTS_SPEC="\
  2. some-command [<options>] <args>...
  3.  
  4. some-command does foo and bar!
  5. --
  6. h,help    show the help
  7.  
  8. foo       some nifty option --foo
  9. bar=      some cool option --bar with an argument
  10. baz=arg   another cool option --baz with a named argument
  11. qux?path  qux may take a path argument but has meaning by itself
  12.  
  13.   An option group Header
  14. C?        option C with an optional argument"
  15.  
  16. eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"

Usage text

When "$@" is -h or —help in the above example, the followingusage text would be shown:

  1. usage: some-command [<options>] <args>...
  2.  
  3.     some-command does foo and bar!
  4.  
  5.     -h, --help            show the help
  6.     --foo                 some nifty option --foo
  7.     --bar ...             some cool option --bar with an argument
  8.     --baz <arg>           another cool option --baz with a named argument
  9.     --qux[=<path>]        qux may take a path argument but has meaning by itself
  10.  
  11. An option group Header
  12.     -C[...]               option C with an optional argument

SQ-QUOTE

In —sq-quote mode, git rev-parse echoes on the standard output asingle line suitable for sh(1) eval. This line is made bynormalizing the arguments following —sq-quote. Nothing other thanquoting the arguments is done.

If you want command input to still be interpreted as usual bygit rev-parse before the output is shell quoted, see the —sqoption.

Example

  1. $ cat >your-git-script.sh <<\EOF
  2. #!/bin/sh
  3. args=$(git rev-parse --sq-quote "$@")   # quote user-supplied arguments
  4. command="git frotz -n24 $args"          # and use it inside a handcrafted
  5.                     # command line
  6. eval "$command"
  7. EOF
  8.  
  9. $ sh your-git-script.sh "a b'c"

EXAMPLES

  • Print the object name of the current commit:
  1. $ git rev-parse --verify HEAD
  • Print the commit object name from the revision in the $REV shell variable:
  1. $ git rev-parse --verify $REV^{commit}

This will error out if $REV is empty or not a valid revision.

  • Similar to above:
  1. $ git rev-parse --default master --verify $REV

but if $REV is empty, the commit object name from master will be printed.

GIT

Part of the git[1] suite