1git-rev-parse(1) 2================ 3 4NAME 5---- 6git-rev-parse - Pick out and massage parameters 7 8 9SYNOPSIS 10-------- 11'git-rev-parse' [ --option ] <args>... 12 13DESCRIPTION 14----------- 15 16Many git porcelainish commands take mixture of flags 17(i.e. parameters that begin with a dash '-') and parameters 18meant for underlying `git-rev-list` command they use internally 19and flags and parameters for other commands they use as the 20downstream of `git-rev-list`. This command is used to 21distinguish between them. 22 23 24OPTIONS 25------- 26--parseopt:: 27 Use `git-rev-parse` in option parsing mode (see PARSEOPT section below). 28 29--keep-dash-dash:: 30 Only meaningful in `--parseopt` mode. Tells the option parser to echo 31 out the first `--` met instead of skipping it. 32 33--revs-only:: 34 Do not output flags and parameters not meant for 35 `git-rev-list` command. 36 37--no-revs:: 38 Do not output flags and parameters meant for 39 `git-rev-list` command. 40 41--flags:: 42 Do not output non-flag parameters. 43 44--no-flags:: 45 Do not output flag parameters. 46 47--default <arg>:: 48 If there is no parameter given by the user, use `<arg>` 49 instead. 50 51--verify:: 52 The parameter given must be usable as a single, valid 53 object name. Otherwise barf and abort. 54 55--sq:: 56 Usually the output is made one line per flag and 57 parameter. This option makes output a single line, 58 properly quoted for consumption by shell. Useful when 59 you expect your parameter to contain whitespaces and 60 newlines (e.g. when using pickaxe `-S` with 61 `git-diff-\*`). 62 63--not:: 64 When showing object names, prefix them with '{caret}' and 65 strip '{caret}' prefix from the object names that already have 66 one. 67 68--symbolic:: 69 Usually the object names are output in SHA1 form (with 70 possible '{caret}' prefix); this option makes them output in a 71 form as close to the original input as possible. 72 73 74--all:: 75 Show all refs found in `$GIT_DIR/refs`. 76 77--branches:: 78 Show branch refs found in `$GIT_DIR/refs/heads`. 79 80--tags:: 81 Show tag refs found in `$GIT_DIR/refs/tags`. 82 83--remotes:: 84 Show tag refs found in `$GIT_DIR/refs/remotes`. 85 86--show-prefix:: 87 When the command is invoked from a subdirectory, show the 88 path of the current directory relative to the top-level 89 directory. 90 91--show-cdup:: 92 When the command is invoked from a subdirectory, show the 93 path of the top-level directory relative to the current 94 directory (typically a sequence of "../", or an empty string). 95 96--git-dir:: 97 Show `$GIT_DIR` if defined else show the path to the .git directory. 98 99--is-inside-git-dir:: 100 When the current working directory is below the repository 101 directory print "true", otherwise "false". 102 103--is-inside-work-tree:: 104 When the current working directory is inside the work tree of the 105 repository print "true", otherwise "false". 106 107--is-bare-repository:: 108 When the repository is bare print "true", otherwise "false". 109 110--short, --short=number:: 111 Instead of outputting the full SHA1 values of object names try to 112 abbreviate them to a shorter unique name. When no length is specified 113 7 is used. The minimum length is 4. 114 115--since=datestring, --after=datestring:: 116 Parses the date string, and outputs corresponding 117 --max-age= parameter for git-rev-list command. 118 119--until=datestring, --before=datestring:: 120 Parses the date string, and outputs corresponding 121 --min-age= parameter for git-rev-list command. 122 123<args>...:: 124 Flags and parameters to be parsed. 125 126 127SPECIFYING REVISIONS 128-------------------- 129 130A revision parameter typically, but not necessarily, names a 131commit object. They use what is called an 'extended SHA1' 132syntax. Here are various ways to spell object names. The 133ones listed near the end of this list are to name trees and 134blobs contained in a commit. 135 136* The full SHA1 object name (40-byte hexadecimal string), or 137 a substring of such that is unique within the repository. 138 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both 139 name the same commit object if there are no other object in 140 your repository whose object name starts with dae86e. 141 142* An output from `git-describe`; i.e. a closest tag, followed by a 143 dash, a `g`, and an abbreviated object name. 144 145* A symbolic ref name. E.g. 'master' typically means the commit 146 object referenced by $GIT_DIR/refs/heads/master. If you 147 happen to have both heads/master and tags/master, you can 148 explicitly say 'heads/master' to tell git which one you mean. 149 When ambiguous, a `<name>` is disambiguated by taking the 150 first match in the following rules: 151 152 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually 153 useful only for `HEAD`, `FETCH_HEAD` and `MERGE_HEAD`); 154 155 . otherwise, `$GIT_DIR/refs/<name>` if exists; 156 157 . otherwise, `$GIT_DIR/refs/tags/<name>` if exists; 158 159 . otherwise, `$GIT_DIR/refs/heads/<name>` if exists; 160 161 . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists; 162 163 . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists. 164 165* A ref followed by the suffix '@' with a date specification 166 enclosed in a brace 167 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1 168 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value 169 of the ref at a prior point in time. This suffix may only be 170 used immediately following a ref name and the ref must have an 171 existing log ($GIT_DIR/logs/<ref>). 172 173* A ref followed by the suffix '@' with an ordinal specification 174 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify 175 the n-th prior value of that ref. For example 'master@\{1\}' 176 is the immediate prior value of 'master' while 'master@\{5\}' 177 is the 5th prior value of 'master'. This suffix may only be used 178 immediately following a ref name and the ref must have an existing 179 log ($GIT_DIR/logs/<ref>). 180 181* You can use the '@' construct with an empty ref part to get at a 182 reflog of the current branch. For example, if you are on the 183 branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'. 184 185* A suffix '{caret}' to a revision parameter means the first parent of 186 that commit object. '{caret}<n>' means the <n>th parent (i.e. 187 'rev{caret}' 188 is equivalent to 'rev{caret}1'). As a special rule, 189 'rev{caret}0' means the commit itself and is used when 'rev' is the 190 object name of a tag object that refers to a commit object. 191 192* A suffix '{tilde}<n>' to a revision parameter means the commit 193 object that is the <n>th generation grand-parent of the named 194 commit object, following only the first parent. I.e. rev~3 is 195 equivalent to rev{caret}{caret}{caret} which is equivalent to 196 rev{caret}1{caret}1{caret}1. See below for a illustration of 197 the usage of this form. 198 199* A suffix '{caret}' followed by an object type name enclosed in 200 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object 201 could be a tag, and dereference the tag recursively until an 202 object of that type is found or the object cannot be 203 dereferenced anymore (in which case, barf). `rev{caret}0` 204 introduced earlier is a short-hand for `rev{caret}\{commit\}`. 205 206* A suffix '{caret}' followed by an empty brace pair 207 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag, 208 and dereference the tag recursively until a non-tag object is 209 found. 210 211* A colon, followed by a slash, followed by a text: this names 212 a commit whose commit message starts with the specified text. 213 This name returns the youngest matching commit which is 214 reachable from any ref. If the commit message starts with a 215 '!', you have to repeat that; the special sequence ':/!', 216 followed by something else than '!' is reserved for now. 217 218* A suffix ':' followed by a path; this names the blob or tree 219 at the given path in the tree-ish object named by the part 220 before the colon. 221 222* A colon, optionally followed by a stage number (0 to 3) and a 223 colon, followed by a path; this names a blob object in the 224 index at the given path. Missing stage number (and the colon 225 that follows it) names an stage 0 entry. During a merge, stage 226 1 is the common ancestor, stage 2 is the target branch's version 227 (typically the current branch), and stage 3 is the version from 228 the branch being merged. 229 230Here is an illustration, by Jon Loeliger. Both node B and C are 231a commit parents of commit node A. Parent commits are ordered 232left-to-right. 233 234 G H I J 235 \ / \ / 236 D E F 237 \ | / \ 238 \ | / | 239 \|/ | 240 B C 241 \ / 242 \ / 243 A 244 245 A = = A^0 246 B = A^ = A^1 = A~1 247 C = A^2 = A^2 248 D = A^^ = A^1^1 = A~2 249 E = B^2 = A^^2 250 F = B^3 = A^^3 251 G = A^^^ = A^1^1^1 = A~3 252 H = D^2 = B^^2 = A^^^2 = A~2^2 253 I = F^ = B^3^ = A^^3^ 254 J = F^2 = B^3^2 = A^^3^2 255 256 257SPECIFYING RANGES 258----------------- 259 260History traversing commands such as `git-log` operate on a set 261of commits, not just a single commit. To these commands, 262specifying a single revision with the notation described in the 263previous section means the set of commits reachable from that 264commit, following the commit ancestry chain. 265 266To exclude commits reachable from a commit, a prefix `{caret}` 267notation is used. E.g. "`{caret}r1 r2`" means commits reachable 268from `r2` but exclude the ones reachable from `r1`. 269 270This set operation appears so often that there is a shorthand 271for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is 272the difference of two sets (subtract the set of commits 273reachable from `r1` from the set of commits reachable from 274`r2`). 275 276A similar notation "`r1\...r2`" is called symmetric difference 277of `r1` and `r2` and is defined as 278"`r1 r2 --not $(git-merge-base --all r1 r2)`". 279It is the set of commits that are reachable from either one of 280`r1` or `r2` but not from both. 281 282Two other shorthands for naming a set that is formed by a commit 283and its parent commits exists. `r1{caret}@` notation means all 284parents of `r1`. `r1{caret}!` includes commit `r1` but excludes 285its all parents. 286 287Here are a handful examples: 288 289 D G H D 290 D F G H I J D F 291 ^G D H D 292 ^D B E I J F B 293 B...C G H D E B C 294 ^D B C E I J F B C 295 C^@ I J F 296 F^! D G H D F 297 298PARSEOPT 299-------- 300 301In `--parseopt` mode, `git-rev-parse` helps massaging options to bring to shell 302scripts the same facilities C builtins have. It works as an option normalizer 303(e.g. splits single switches aggregate values), a bit like `getopt(1)` does. 304 305It takes on the standard input the specification of the options to parse and 306understand, and echoes on the standard output a line suitable for `sh(1)` `eval` 307to replace the arguments with normalized ones. In case of error, it outputs 308usage on the standard error stream, and exits with code 129. 309 310Input Format 311~~~~~~~~~~~~ 312 313`git-rev-parse --parseopt` input format is fully text based. It has two parts, 314separated by a line that contains only `--`. The lines before the separator 315(should be more than one) are used for the usage. 316The lines after the separator describe the options. 317 318Each line of options has this format: 319 320------------ 321<opt_spec><arg_spec>? SP+ help LF 322------------ 323 324`<opt_spec>`:: 325 its format is the short option character, then the long option name 326 separated by a comma. Both parts are not required, though at least one 327 is necessary. `h,help`, `dry-run` and `f` are all three correct 328 `<opt_spec>`. 329 330`<arg_spec>`:: 331 an `<arg_spec>` tells the option parser if the option has an argument 332 (`=`), an optional one (`?` though its use is discouraged) or none 333 (no `<arg_spec>` in that case). 334 335The remainder of the line, after stripping the spaces, is used 336as the help associated to the option. 337 338Blank lines are ignored, and lines that don't match this specification are used 339as option group headers (start the line with a space to create such 340lines on purpose). 341 342Example 343~~~~~~~ 344 345------------ 346OPTS_SPEC="\ 347some-command [options] <args>... 348 349some-command does foo and bar! 350-- 351h,help show the help 352 353foo some nifty option --foo 354bar= some cool option --bar with an argument 355 356 An option group Header 357C? option C with an optional argument" 358 359eval `echo "$OPTS_SPEC" | git-rev-parse --parseopt -- "$@" || echo exit $?` 360------------ 361 362 363Author 364------ 365Written by Linus Torvalds <torvalds@osdl.org> . 366Junio C Hamano <junkio@cox.net> and Pierre Habouzit <madcoder@debian.org> 367 368Documentation 369-------------- 370Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. 371 372GIT 373--- 374Part of the gitlink:git[7] suite