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. 115 116* The full SHA1 object name (40-byte hexadecimal string), or 117 a substring of such that is unique within the repository. 118 E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both 119 name the same commit object if there are no other object in 120 your repository whose object name starts with dae86e. 121 122* A symbolic ref name. E.g. 'master' typically means the commit 123 object referenced by $GIT_DIR/refs/heads/master. If you 124 happen to have both heads/master and tags/master, you can 125 explicitly say 'heads/master' to tell git which one you mean. 126 127* A suffix '@' followed by a date specification enclosed in a brace 128 pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1 129 second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value 130 of the ref at a prior point in time. This suffix may only be 131 used immediately following a ref name and the ref must have an 132 existing log ($GIT_DIR/logs/<ref>). 133 134* A suffix '{caret}' to a revision parameter means the first parent of 135 that commit object. '{caret}<n>' means the <n>th parent (i.e. 136 'rev{caret}' 137 is equivalent to 'rev{caret}1'). As a special rule, 138 'rev{caret}0' means the commit itself and is used when 'rev' is the 139 object name of a tag object that refers to a commit object. 140 141* A suffix '~<n>' to a revision parameter means the commit 142 object that is the <n>th generation grand-parent of the named 143 commit object, following only the first parent. I.e. rev~3 is 144 equivalent to rev{caret}{caret}{caret} which is equivalent to\ 145 rev{caret}1{caret}1{caret}1. 146 147* A suffix '{caret}' followed by an object type name enclosed in 148 brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object 149 could be a tag, and dereference the tag recursively until an 150 object of that type is found or the object cannot be 151 dereferenced anymore (in which case, barf). `rev{caret}0` 152 introduced earlier is a short-hand for `rev{caret}\{commit\}`. 153 154* A suffix '{caret}' followed by an empty brace pair 155 (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag, 156 and dereference the tag recursively until a non-tag object is 157 found. 158 159Here is an illustration, by Jon Loeliger. Both node B and C are 160a commit parents of commit node A. Parent commits are ordered 161left-to-right. 162 163 G H I J 164 \ / \ / 165 D E F 166 \ | / \ 167 \ | / | 168 \|/ | 169 B C 170 \ / 171 \ / 172 A 173 174 A = = A^0 175 B = A^ = A^1 = A~1 176 C = A^2 = A^2 177 D = A^^ = A^1^1 = A~2 178 E = B^2 = A^^2 179 F = B^3 = A^^3 180 G = A^^^ = A^1^1^1 = A~3 181 H = D^2 = B^^2 = A^^^2 = A~2^2 182 I = F^ = B^3^ = A^^3^ 183 J = F^2 = B^3^2 = A^^3^2 184 185 186SPECIFYING RANGES 187----------------- 188 189History traversing commands such as `git-log` operate on a set 190of commits, not just a single commit. To these commands, 191specifying a single revision with the notation described in the 192previous section means the set of commits reachable from that 193commit, following the commit ancestry chain. 194 195To exclude commits reachable from a commit, a prefix `{caret}` 196notation is used. E.g. "`{caret}r1 r2`" means commits reachable 197from `r2` but exclude the ones reachable from `r1`. 198 199This set operation appears so often that there is a shorthand 200for it. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is 201the difference of two sets (subtract the set of commits 202reachable from `r1` from the set of commits reachable from 203`r2`). 204 205A similar notation "`r1\...r2`" is called symmetric difference 206of `r1` and `r2` and is defined as 207"`r1 r2 --not $(git-merge-base --all r1 r2)`". 208It it the set of commits that are reachable from either one of 209`r1` or `r2` but not from both. 210 211Here are a few examples: 212 213 D A B D 214 D F A B C D F 215 ^A G B D 216 ^A F B C F 217 G...I C D F G I 218 ^B G I C D F G I 219 220Author 221------ 222Written by Linus Torvalds <torvalds@osdl.org> and 223Junio C Hamano <junkio@cox.net> 224 225Documentation 226-------------- 227Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. 228 229GIT 230--- 231Part of the gitlink:git[7] suite 232