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--revs-only:: 27 Do not output flags and parameters not meant for 28 `git-rev-list` command. 29 30--no-revs:: 31 Do not output flags and parameters meant for 32 `git-rev-list` command. 33 34--flags:: 35 Do not output non-flag parameters. 36 37--no-flags:: 38 Do not output flag parameters. 39 40--default <arg>:: 41 If there is no parameter given by the user, use `<arg>` 42 instead. 43 44--verify:: 45 The parameter given must be usable as a single, valid 46 object name. Otherwise barf and abort. 47 48--sq:: 49 Usually the output is made one line per flag and 50 parameter. This option makes output a single line, 51 properly quoted for consumption by shell. Useful when 52 you expect your parameter to contain whitespaces and 53 newlines (e.g. when using pickaxe `-S` with 54 `git-diff-\*`). 55 56--not:: 57 When showing object names, prefix them with '{caret}' and 58 strip '{caret}' prefix from the object names that already have 59 one. 60 61--symbolic:: 62 Usually the object names are output in SHA1 form (with 63 possible '{caret}' prefix); this option makes them output in a 64 form as close to the original input as possible. 65 66 67--all:: 68 Show all refs found in `$GIT_DIR/refs`. 69 70--branches:: 71 Show branch refs found in `$GIT_DIR/refs/heads`. 72 73--tags:: 74 Show tag refs found in `$GIT_DIR/refs/tags`. 75 76--remotes:: 77 Show tag refs found in `$GIT_DIR/refs/remotes`. 78 79--show-prefix:: 80 When the command is invoked from a subdirectory, show the 81 path of the current directory relative to the top-level 82 directory. 83 84--show-cdup:: 85 When the command is invoked from a subdirectory, show the 86 path of the top-level directory relative to the current 87 directory (typically a sequence of "../", or an empty string). 88 89--git-dir:: 90 Show `$GIT_DIR` if defined else show the path to the .git directory. 91 92--short, --short=number:: 93 Instead of outputting the full SHA1 values of object names try to 94 abbreviate them to a shorter unique name. When no length is specified 95 7 is used. The minimum length is 4. 96 97--since=datestring, --after=datestring:: 98 Parses the date string, and outputs corresponding 99 --max-age= parameter for git-rev-list command. 100 101--until=datestring, --before=datestring:: 102 Parses the date string, and outputs corresponding 103 --min-age= parameter for git-rev-list command. 104 105<args>...:: 106 Flags and parameters to be parsed. 107 108 109SPECIFYING REVISIONS 110-------------------- 111 112A revision parameter typically, but not necessarily, names a 113commit object. They use what is called an 'extended SHA1' 114syntax. Here are various ways to spell object names. The 115ones listed near the end of this list are to name trees and 116blobs contained in a commit. 117 118* The full SHA1 object name (40-byte hexadecimal string), or 119 a substring of such that is unique within the repository. 120 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both 121 name the same commit object if there are no other object in 122 your repository whose object name starts with dae86e. 123 124* An output from `git-describe`; i.e. a closest tag, followed by a 125 dash, a `g`, and an abbreviated object name. 126 127* A symbolic ref name. E.g. 'master' typically means the commit 128 object referenced by $GIT_DIR/refs/heads/master. If you 129 happen to have both heads/master and tags/master, you can 130 explicitly say 'heads/master' to tell git which one you mean. 131 When ambiguous, a `<name>` is disambiguated by taking the 132 first match in the following rules: 133 134 . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually 135 useful only for `HEAD`, `FETCH_HEAD` and `MERGE_HEAD`); 136 137 . otherwise, `$GIT_DIR/refs/<name>` if exists; 138 139 . otherwise, `$GIT_DIR/refs/tags/<name>` if exists; 140 141 . otherwise, `$GIT_DIR/refs/heads/<name>` if exists; 142 143 . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists; 144 145 . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists. 146 147* A ref followed by the suffix '@' with a date specification 148 enclosed in a brace 149 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1 150 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value 151 of the ref at a prior point in time. This suffix may only be 152 used immediately following a ref name and the ref must have an 153 existing log ($GIT_DIR/logs/<ref>). 154 155* A ref followed by the suffix '@' with an ordinal specification 156 enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify 157 the n-th prior value of that ref. For example 'master@\{1\}' 158 is the immediate prior value of 'master' while 'master@\{5\}' 159 is the 5th prior value of 'master'. This suffix may only be used 160 immediately following a ref name and the ref must have an existing 161 log ($GIT_DIR/logs/<ref>). 162 163* A suffix '{caret}' to a revision parameter means the first parent of 164 that commit object. '{caret}<n>' means the <n>th parent (i.e. 165 'rev{caret}' 166 is equivalent to 'rev{caret}1'). As a special rule, 167 'rev{caret}0' means the commit itself and is used when 'rev' is the 168 object name of a tag object that refers to a commit object. 169 170* A suffix '{tilde}<n>' to a revision parameter means the commit 171 object that is the <n>th generation grand-parent of the named 172 commit object, following only the first parent. I.e. rev~3 is 173 equivalent to rev{caret}{caret}{caret} which is equivalent to 174 rev{caret}1{caret}1{caret}1. See below for a illustration of 175 the usage of this form. 176 177* A suffix '{caret}' followed by an object type name enclosed in 178 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object 179 could be a tag, and dereference the tag recursively until an 180 object of that type is found or the object cannot be 181 dereferenced anymore (in which case, barf). `rev{caret}0` 182 introduced earlier is a short-hand for `rev{caret}\{commit\}`. 183 184* A suffix '{caret}' followed by an empty brace pair 185 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag, 186 and dereference the tag recursively until a non-tag object is 187 found. 188 189* A suffix ':' followed by a path; this names the blob or tree 190 at the given path in the tree-ish object named by the part 191 before the colon. 192 193* A colon, optionally followed by a stage number (0 to 3) and a 194 colon, followed by a path; this names a blob object in the 195 index at the given path. Missing stage number (and the colon 196 that follows it) names an stage 0 entry. 197 198Here is an illustration, by Jon Loeliger. Both node B and C are 199a commit parents of commit node A. Parent commits are ordered 200left-to-right. 201 202 G H I J 203 \ / \ / 204 D E F 205 \ | / \ 206 \ | / | 207 \|/ | 208 B C 209 \ / 210 \ / 211 A 212 213 A = = A^0 214 B = A^ = A^1 = A~1 215 C = A^2 = A^2 216 D = A^^ = A^1^1 = A~2 217 E = B^2 = A^^2 218 F = B^3 = A^^3 219 G = A^^^ = A^1^1^1 = A~3 220 H = D^2 = B^^2 = A^^^2 = A~2^2 221 I = F^ = B^3^ = A^^3^ 222 J = F^2 = B^3^2 = A^^3^2 223 224 225SPECIFYING RANGES 226----------------- 227 228History traversing commands such as `git-log` operate on a set 229of commits, not just a single commit. To these commands, 230specifying a single revision with the notation described in the 231previous section means the set of commits reachable from that 232commit, following the commit ancestry chain. 233 234To exclude commits reachable from a commit, a prefix `{caret}` 235notation is used. E.g. "`{caret}r1 r2`" means commits reachable 236from `r2` but exclude the ones reachable from `r1`. 237 238This set operation appears so often that there is a shorthand 239for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is 240the difference of two sets (subtract the set of commits 241reachable from `r1` from the set of commits reachable from 242`r2`). 243 244A similar notation "`r1\...r2`" is called symmetric difference 245of `r1` and `r2` and is defined as 246"`r1 r2 --not $(git-merge-base --all r1 r2)`". 247It it the set of commits that are reachable from either one of 248`r1` or `r2` but not from both. 249 250Two other shorthands for naming a set that is formed by a commit 251and its parent commits exists. `r1{caret}@` notation means all 252parents of `r1`. `r1{caret}!` includes commit `r1` but excludes 253its all parents. 254 255Here are a handful examples: 256 257 D A B D 258 D F A B C D F 259 ^A G B D 260 ^A F B C F 261 G...I C D F G I 262 ^B G I C D F G I 263 F^@ A B C 264 F^! H D F H 265 266Author 267------ 268Written by Linus Torvalds <torvalds@osdl.org> and 269Junio C Hamano <junkio@cox.net> 270 271Documentation 272-------------- 273Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. 274 275GIT 276--- 277Part of the gitlink:git[7] suite 278