Documentation/git-rev-parse.txt

   1 git-rev-parse(1)
   2 ================
   3
   4 NAME
   5 ----
   6 git-rev-parse - Pick out and massage parameters
   7
   8
   9 SYNOPSIS
  10 --------
  11 [verse]
  12 'git rev-parse' [<options>] <args>...
  13
  14 DESCRIPTION
  15 -----------
  16
  17 Many Git porcelainish commands take mixture of flags
  18 (i.e. parameters that begin with a dash '-') and parameters
  19 meant for the underlying 'git rev-list' command they use internally
  20 and flags and parameters for the other commands they use
  21 downstream of 'git rev-list'.  This command is used to
  22 distinguish between them.
  23
  24
  25 OPTIONS
  26 -------
  27
  28 Operation Modes
  29 ~~~~~~~~~~~~~~~
  30
  31 Each of these options must appear first on the command line.
  32
  33 --parseopt::
  34         Use 'git rev-parse' in option parsing mode (see PARSEOPT section below).
  35
  36 --sq-quote::
  37         Use 'git rev-parse' in shell quoting mode (see SQ-QUOTE
  38         section below). In contrast to the `--sq` option below, this
  39         mode does only quoting. Nothing else is done to command input.
  40
  41 Options for --parseopt
  42 ~~~~~~~~~~~~~~~~~~~~~~
  43
  44 --keep-dashdash::
  45         Only meaningful in `--parseopt` mode. Tells the option parser to echo
  46         out the first `--` met instead of skipping it.
  47
  48 --stop-at-non-option::
  49         Only meaningful in `--parseopt` mode.  Lets the option parser stop at
  50         the first non-option argument.  This can be used to parse sub-commands
  51         that take options themselves.
  52
  53 --stuck-long::
  54         Only meaningful in `--parseopt` mode. Output the options in their
  55         long form if available, and with their arguments stuck.
  56
  57 Options for Filtering
  58 ~~~~~~~~~~~~~~~~~~~~~
  59
  60 --revs-only::
  61         Do not output flags and parameters not meant for
  62         'git rev-list' command.
  63
  64 --no-revs::
  65         Do not output flags and parameters meant for
  66         'git rev-list' command.
  67
  68 --flags::
  69         Do not output non-flag parameters.
  70
  71 --no-flags::
  72         Do not output flag parameters.
  73
  74 Options for Output
  75 ~~~~~~~~~~~~~~~~~~
  76
  77 --default <arg>::
  78         If there is no parameter given by the user, use `<arg>`
  79         instead.
  80
  81 --prefix <arg>::
  82         Behave as if 'git rev-parse' was invoked from the `<arg>`
  83         subdirectory of the working tree.  Any relative filenames are
  84         resolved as if they are prefixed by `<arg>` and will be printed
  85         in that form.
  86 +
  87 This can be used to convert arguments to a command run in a subdirectory
  88 so that they can still be used after moving to the top-level of the
  89 repository.  For example:
  90 +
  91 ----
  92 prefix=$(git rev-parse --show-prefix)
  93 cd "$(git rev-parse --show-toplevel)"
  94 # rev-parse provides the -- needed for 'set'
  95 eval "set $(git rev-parse --sq --prefix "$prefix" -- "$@")"
  96 ----
  97
  98 --verify::
  99         Verify that exactly one parameter is provided, and that it
 100         can be turned into a raw 20-byte SHA-1 that can be used to
 101         access the object database. If so, emit it to the standard
 102         output; otherwise, error out.
 103 +
 104 If you want to make sure that the output actually names an object in
 105 your object database and/or can be used as a specific type of object
 106 you require, you can add the `^{type}` peeling operator to the parameter.
 107 For example, `git rev-parse "$VAR^{commit}"` will make sure `$VAR`
 108 names an existing object that is a commit-ish (i.e. a commit, or an
 109 annotated tag that points at a commit).  To make sure that `$VAR`
 110 names an existing object of any type, `git rev-parse "$VAR^{object}"`
 111 can be used.
 112
 113 -q::
 114 --quiet::
 115         Only meaningful in `--verify` mode. Do not output an error
 116         message if the first argument is not a valid object name;
 117         instead exit with non-zero status silently.
 118         SHA-1s for valid object names are printed to stdout on success.
 119
 120 --sq::
 121         Usually the output is made one line per flag and
 122         parameter.  This option makes output a single line,
 123         properly quoted for consumption by shell.  Useful when
 124         you expect your parameter to contain whitespaces and
 125         newlines (e.g. when using pickaxe `-S` with
 126         'git diff-{asterisk}'). In contrast to the `--sq-quote` option,
 127         the command input is still interpreted as usual.
 128
 129 --short[=length]::
 130         Same as `--verify` but shortens the object name to a unique
 131         prefix with at least `length` characters. The minimum length
 132         is 4, the default is the effective value of the `core.abbrev`
 133         configuration variable (see linkgit:git-config[1]).
 134
 135 --not::
 136         When showing object names, prefix them with '{caret}' and
 137         strip '{caret}' prefix from the object names that already have
 138         one.
 139
 140 --abbrev-ref[=(strict|loose)]::
 141         A non-ambiguous short name of the objects name.
 142         The option core.warnAmbiguousRefs is used to select the strict
 143         abbreviation mode.
 144
 145 --symbolic::
 146         Usually the object names are output in SHA-1 form (with
 147         possible '{caret}' prefix); this option makes them output in a
 148         form as close to the original input as possible.
 149
 150 --symbolic-full-name::
 151         This is similar to --symbolic, but it omits input that
 152         are not refs (i.e. branch or tag names; or more
 153         explicitly disambiguating "heads/master" form, when you
 154         want to name the "master" branch when there is an
 155         unfortunately named tag "master"), and show them as full
 156         refnames (e.g. "refs/heads/master").
 157
 158 Options for Objects
 159 ~~~~~~~~~~~~~~~~~~~
 160
 161 --all::
 162         Show all refs found in `refs/`.
 163
 164 --branches[=pattern]::
 165 --tags[=pattern]::
 166 --remotes[=pattern]::
 167         Show all branches, tags, or remote-tracking branches,
 168         respectively (i.e., refs found in `refs/heads`,
 169         `refs/tags`, or `refs/remotes`, respectively).
 170 +
 171 If a `pattern` is given, only refs matching the given shell glob are
 172 shown.  If the pattern does not contain a globbing character (`?`,
 173 `*`, or `[`), it is turned into a prefix match by appending `/*`.
 174
 175 --glob=pattern::
 176         Show all refs matching the shell glob pattern `pattern`. If
 177         the pattern does not start with `refs/`, this is automatically
 178         prepended.  If the pattern does not contain a globbing
 179         character (`?`, `*`, or `[`), it is turned into a prefix
 180         match by appending `/*`.
 181
 182 --exclude=<glob-pattern>::
 183         Do not include refs matching '<glob-pattern>' that the next `--all`,
 184         `--branches`, `--tags`, `--remotes`, or `--glob` would otherwise
 185         consider. Repetitions of this option accumulate exclusion patterns
 186         up to the next `--all`, `--branches`, `--tags`, `--remotes`, or
 187         `--glob` option (other options or arguments do not clear
 188         accumulated patterns).
 189 +
 190 The patterns given should not begin with `refs/heads`, `refs/tags`, or
 191 `refs/remotes` when applied to `--branches`, `--tags`, or `--remotes`,
 192 respectively, and they must begin with `refs/` when applied to `--glob`
 193 or `--all`. If a trailing '/{asterisk}' is intended, it must be given
 194 explicitly.
 195
 196 --disambiguate=<prefix>::
 197         Show every object whose name begins with the given prefix.
 198         The <prefix> must be at least 4 hexadecimal digits long to
 199         avoid listing each and every object in the repository by
 200         mistake.
 201
 202 Options for Files
 203 ~~~~~~~~~~~~~~~~~
 204
 205 --local-env-vars::
 206         List the GIT_* environment variables that are local to the
 207         repository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).
 208         Only the names of the variables are listed, not their value,
 209         even if they are set.
 210
 211 --git-dir::
 212         Show `$GIT_DIR` if defined. Otherwise show the path to
 213         the .git directory. The path shown, when relative, is
 214         relative to the current working directory.
 215 +
 216 If `$GIT_DIR` is not defined and the current directory
 217 is not detected to lie in a Git repository or work tree
 218 print a message to stderr and exit with nonzero status.
 219
 220 --absolute-git-dir::
 221         Like `--git-dir`, but its output is always the canonicalized
 222         absolute path.
 223
 224 --git-common-dir::
 225         Show `$GIT_COMMON_DIR` if defined, else `$GIT_DIR`.
 226
 227 --is-inside-git-dir::
 228         When the current working directory is below the repository
 229         directory print "true", otherwise "false".
 230
 231 --is-inside-work-tree::
 232         When the current working directory is inside the work tree of the
 233         repository print "true", otherwise "false".
 234
 235 --is-bare-repository::
 236         When the repository is bare print "true", otherwise "false".
 237
 238 --is-shallow-repository::
 239         When the repository is shallow print "true", otherwise "false".
 240
 241 --resolve-git-dir <path>::
 242         Check if <path> is a valid repository or a gitfile that
 243         points at a valid repository, and print the location of the
 244         repository.  If <path> is a gitfile then the resolved path
 245         to the real repository is printed.
 246
 247 --git-path <path>::
 248         Resolve "$GIT_DIR/<path>" and takes other path relocation
 249         variables such as $GIT_OBJECT_DIRECTORY,
 250         $GIT_INDEX_FILE... into account. For example, if
 251         $GIT_OBJECT_DIRECTORY is set to /foo/bar then "git rev-parse
 252         --git-path objects/abc" returns /foo/bar/abc.
 253
 254 --show-cdup::
 255         When the command is invoked from a subdirectory, show the
 256         path of the top-level directory relative to the current
 257         directory (typically a sequence of "../", or an empty string).
 258
 259 --show-prefix::
 260         When the command is invoked from a subdirectory, show the
 261         path of the current directory relative to the top-level
 262         directory.
 263
 264 --show-toplevel::
 265         Show the absolute path of the top-level directory.
 266
 267 --show-superproject-working-tree::
 268         Show the absolute path of the root of the superproject's
 269         working tree (if exists) that uses the current repository as
 270         its submodule.  Outputs nothing if the current repository is
 271         not used as a submodule by any project.
 272
 273 --shared-index-path::
 274         Show the path to the shared index file in split index mode, or
 275         empty if not in split-index mode.
 276
 277 --show-object-format[=(storage|input|output)]::
 278         Show the object format (hash algorithm) used for the repository
 279         for storage inside the `.git` directory, input, or output. For
 280         input, multiple algorithms may be printed, space-separated.
 281         If not specified, the default is "storage".
 282
 283
 284 Other Options
 285 ~~~~~~~~~~~~~
 286
 287 --since=datestring::
 288 --after=datestring::
 289         Parse the date string, and output the corresponding
 290         --max-age= parameter for 'git rev-list'.
 291
 292 --until=datestring::
 293 --before=datestring::
 294         Parse the date string, and output the corresponding
 295         --min-age= parameter for 'git rev-list'.
 296
 297 <args>...::
 298         Flags and parameters to be parsed.
 299
 300
 301 include::revisions.txt[]
 302
 303 PARSEOPT
 304 --------
 305
 306 In `--parseopt` mode, 'git rev-parse' helps massaging options to bring to shell
 307 scripts the same facilities C builtins have. It works as an option normalizer
 308 (e.g. splits single switches aggregate values), a bit like `getopt(1)` does.
 309
 310 It takes on the standard input the specification of the options to parse and
 311 understand, and echoes on the standard output a string suitable for `sh(1)` `eval`
 312 to replace the arguments with normalized ones.  In case of error, it outputs
 313 usage on the standard error stream, and exits with code 129.
 314
 315 Note: Make sure you quote the result when passing it to `eval`.  See
 316 below for an example.
 317
 318 Input Format
 319 ~~~~~~~~~~~~
 320
 321 'git rev-parse --parseopt' input format is fully text based. It has two parts,
 322 separated by a line that contains only `--`. The lines before the separator
 323 (should be one or more) are used for the usage.
 324 The lines after the separator describe the options.
 325
 326 Each line of options has this format:
 327
 328 ------------
 329 <opt-spec><flags>*<arg-hint>? SP+ help LF
 330 ------------
 331
 332 `<opt-spec>`::
 333         its format is the short option character, then the long option name
 334         separated by a comma. Both parts are not required, though at least one
 335         is necessary. May not contain any of the `<flags>` characters.
 336         `h,help`, `dry-run` and `f` are examples of correct `<opt-spec>`.
 337
 338 `<flags>`::
 339         `<flags>` are of `*`, `=`, `?` or `!`.
 340         * Use `=` if the option takes an argument.
 341
 342         * Use `?` to mean that the option takes an optional argument. You
 343           probably want to use the `--stuck-long` mode to be able to
 344           unambiguously parse the optional argument.
 345
 346         * Use `*` to mean that this option should not be listed in the usage
 347           generated for the `-h` argument. It's shown for `--help-all` as
 348           documented in linkgit:gitcli[7].
 349
 350         * Use `!` to not make the corresponding negated long option available.
 351
 352 `<arg-hint>`::
 353         `<arg-hint>`, if specified, is used as a name of the argument in the
 354         help output, for options that take arguments. `<arg-hint>` is
 355         terminated by the first whitespace.  It is customary to use a
 356         dash to separate words in a multi-word argument hint.
 357
 358 The remainder of the line, after stripping the spaces, is used
 359 as the help associated to the option.
 360
 361 Blank lines are ignored, and lines that don't match this specification are used
 362 as option group headers (start the line with a space to create such
 363 lines on purpose).
 364
 365 Example
 366 ~~~~~~~
 367
 368 ------------
 369 OPTS_SPEC="\
 370 some-command [<options>] <args>...
 371
 372 some-command does foo and bar!
 373 --
 374 h,help    show the help
 375
 376 foo       some nifty option --foo
 377 bar=      some cool option --bar with an argument
 378 baz=arg   another cool option --baz with a named argument
 379 qux?path  qux may take a path argument but has meaning by itself
 380
 381   An option group Header
 382 C?        option C with an optional argument"
 383
 384 eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"
 385 ------------
 386
 387
 388 Usage text
 389 ~~~~~~~~~~
 390
 391 When `"$@"` is `-h` or `--help` in the above example, the following
 392 usage text would be shown:
 393
 394 ------------
 395 usage: some-command [<options>] <args>...
 396
 397     some-command does foo and bar!
 398
 399     -h, --help            show the help
 400     --foo                 some nifty option --foo
 401     --bar ...             some cool option --bar with an argument
 402     --baz <arg>           another cool option --baz with a named argument
 403     --qux[=<path>]        qux may take a path argument but has meaning by itself
 404
 405 An option group Header
 406     -C[...]               option C with an optional argument
 407 ------------
 408
 409 SQ-QUOTE
 410 --------
 411
 412 In `--sq-quote` mode, 'git rev-parse' echoes on the standard output a
 413 single line suitable for `sh(1)` `eval`. This line is made by
 414 normalizing the arguments following `--sq-quote`. Nothing other than
 415 quoting the arguments is done.
 416
 417 If you want command input to still be interpreted as usual by
 418 'git rev-parse' before the output is shell quoted, see the `--sq`
 419 option.
 420
 421 Example
 422 ~~~~~~~
 423
 424 ------------
 425 $ cat >your-git-script.sh <<\EOF
 426 #!/bin/sh
 427 args=$(git rev-parse --sq-quote "$@")   # quote user-supplied arguments
 428 command="git frotz -n24 $args"          # and use it inside a handcrafted
 429                                         # command line
 430 eval "$command"
 431 EOF
 432
 433 $ sh your-git-script.sh "a b'c"
 434 ------------
 435
 436 EXAMPLES
 437 --------
 438
 439 * Print the object name of the current commit:
 440 +
 441 ------------
 442 $ git rev-parse --verify HEAD
 443 ------------
 444
 445 * Print the commit object name from the revision in the $REV shell variable:
 446 +
 447 ------------
 448 $ git rev-parse --verify $REV^{commit}
 449 ------------
 450 +
 451 This will error out if $REV is empty or not a valid revision.
 452
 453 * Similar to above:
 454 +
 455 ------------
 456 $ git rev-parse --default master --verify $REV
 457 ------------
 458 +
 459 but if $REV is empty, the commit object name from master will be printed.
 460
 461 GIT
 462 ---
 463 Part of the linkgit:git[1] suite