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diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt new file mode 100644 index 0000000000..e7845d4055 --- /dev/null +++ b/Documentation/git-rev-parse.txt @@ -0,0 +1,501 @@ +git-rev-parse(1) +================ + +NAME +---- +git-rev-parse - Pick out and massage parameters + + +SYNOPSIS +-------- +'git rev-parse' [ --option ] <args>... + +DESCRIPTION +----------- + +Many git porcelainish commands take mixture of flags +(i.e. parameters that begin with a dash '-') and parameters +meant for the underlying 'git rev-list' command they use internally +and flags and parameters for the other commands they use +downstream of 'git rev-list'. This command is used to +distinguish between them. + + +OPTIONS +------- +--parseopt:: + Use 'git rev-parse' in option parsing mode (see PARSEOPT section below). + +--keep-dashdash:: + Only meaningful in `--parseopt` mode. Tells the option parser to echo + out the first `--` met instead of skipping it. + +--stop-at-non-option:: + Only meaningful in `--parseopt` mode. Lets the option parser stop at + the first non-option argument. This can be used to parse sub-commands + that take options themself. + +--sq-quote:: + Use 'git rev-parse' in shell quoting mode (see SQ-QUOTE + section below). In contrast to the `--sq` option below, this + mode does only quoting. Nothing else is done to command input. + +--revs-only:: + Do not output flags and parameters not meant for + 'git rev-list' command. + +--no-revs:: + Do not output flags and parameters meant for + 'git rev-list' command. + +--flags:: + Do not output non-flag parameters. + +--no-flags:: + Do not output flag parameters. + +--default <arg>:: + If there is no parameter given by the user, use `<arg>` + instead. + +--verify:: + The parameter given must be usable as a single, valid + object name. Otherwise barf and abort. + +-q:: +--quiet:: + Only meaningful in `--verify` mode. Do not output an error + message if the first argument is not a valid object name; + instead exit with non-zero status silently. + +--sq:: + Usually the output is made one line per flag and + parameter. This option makes output a single line, + properly quoted for consumption by shell. Useful when + you expect your parameter to contain whitespaces and + newlines (e.g. when using pickaxe `-S` with + 'git diff-\*'). In contrast to the `--sq-quote` option, + the command input is still interpreted as usual. + +--not:: + When showing object names, prefix them with '{caret}' and + strip '{caret}' prefix from the object names that already have + one. + +--symbolic:: + Usually the object names are output in SHA1 form (with + possible '{caret}' prefix); this option makes them output in a + form as close to the original input as possible. + +--symbolic-full-name:: + This is similar to \--symbolic, but it omits input that + are not refs (i.e. branch or tag names; or more + explicitly disambiguating "heads/master" form, when you + want to name the "master" branch when there is an + unfortunately named tag "master"), and show them as full + refnames (e.g. "refs/heads/master"). + +--abbrev-ref[={strict|loose}]:: + A non-ambiguous short name of the objects name. + The option core.warnAmbiguousRefs is used to select the strict + abbreviation mode. + +--all:: + Show all refs found in `$GIT_DIR/refs`. + +--branches[=pattern]:: +--tags[=pattern]:: +--remotes[=pattern]:: + Show all branches, tags, or remote-tracking branches, + respectively (i.e., refs found in `$GIT_DIR/refs/heads`, + `$GIT_DIR/refs/tags`, or `$GIT_DIR/refs/remotes`, + respectively). ++ +If a `pattern` is given, only refs matching the given shell glob are +shown. 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`. If + the pattern does not start with `refs/`, this is automatically + prepended. If the pattern does not contain a globbing + character (`?`, `\*`, or `[`), it is turned into a prefix + match by appending `/\*`. + +--show-toplevel:: + Show the absolute path of the top-level directory. + +--show-prefix:: + When the command is invoked from a subdirectory, show the + path of the current directory relative to the top-level + directory. + +--show-cdup:: + When the command is invoked from a subdirectory, show the + path of the top-level directory relative to the current + directory (typically a sequence of "../", or an empty string). + +--git-dir:: + Show `$GIT_DIR` if defined else show the path to the .git directory. + +--is-inside-git-dir:: + When the current working directory is below the repository + directory print "true", otherwise "false". + +--is-inside-work-tree:: + When the current working directory is inside the work tree of the + repository print "true", otherwise "false". + +--is-bare-repository:: + When the repository is bare print "true", otherwise "false". + +--short:: +--short=number:: + Instead of outputting the full SHA1 values of object names try to + abbreviate them to a shorter unique name. When no length is specified + 7 is used. The minimum length is 4. + +--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'. + +<args>...:: + Flags and parameters to be parsed. + + +SPECIFYING REVISIONS +-------------------- + +A revision parameter typically, but not necessarily, names a +commit object. They use what is called an 'extended SHA1' +syntax. Here are various ways to spell object names. The +ones listed near the end of this list are to name trees and +blobs contained in a commit. + +* The full SHA1 object name (40-byte hexadecimal string), or + a substring of such that is unique within the repository. + E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both + name the same commit object if there are no other object in + your repository whose object name starts with dae86e. + +* An output from 'git describe'; i.e. a closest tag, optionally + followed by a dash and a number of commits, followed by a dash, a + `g`, and an abbreviated object name. + +* A symbolic ref name. E.g. 'master' typically means the commit + object referenced by $GIT_DIR/refs/heads/master. If you + happen to have both heads/master and tags/master, you can + explicitly say 'heads/master' to tell git which one you mean. + When ambiguous, a `<name>` is disambiguated by taking the + first match in the following rules: + + . if `$GIT_DIR/<name>` exists, that is what you mean (this is usually + useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`); + + . otherwise, `$GIT_DIR/refs/<name>` if exists; + + . otherwise, `$GIT_DIR/refs/tags/<name>` if exists; + + . otherwise, `$GIT_DIR/refs/heads/<name>` if exists; + + . otherwise, `$GIT_DIR/refs/remotes/<name>` if exists; + + . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists. ++ +HEAD names the commit your changes in the working tree is based on. +FETCH_HEAD records the branch you fetched from a remote repository +with your last 'git fetch' invocation. +ORIG_HEAD is created by commands that moves your HEAD in a drastic +way, to record the position of the HEAD before their operation, so that +you can change the tip of the branch back to the state before you ran +them easily. +MERGE_HEAD records the commit(s) you are merging into your branch +when you run 'git merge'. + +* A ref followed by the suffix '@' with a date specification + enclosed in a brace + pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1 + second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value + of the ref at a prior point in time. This suffix may only be + used immediately following a ref name and the ref must have an + existing log ($GIT_DIR/logs/<ref>). Note that this looks up the state + of your *local* ref at a given time; e.g., what was in your local + `master` branch last week. If you want to look at commits made during + certain times, see `--since` and `--until`. + +* A ref followed by the suffix '@' with an ordinal specification + enclosed in a brace pair (e.g. '\{1\}', '\{15\}') to specify + the 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 used + immediately following a ref name and the ref must have an existing + log ($GIT_DIR/logs/<ref>). + +* You can use the '@' construct with an empty ref part to get at a + reflog of the current branch. For example, if you are on the + branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'. + +* The special construct '@\{-<n>\}' means the <n>th branch checked out + before the current one. + +* The suffix '@{upstream}' to a ref (short form 'ref@{u}') refers to + the branch the ref is set to build on top of. Missing ref defaults + to the current branch. + +* A suffix '{caret}' to a revision parameter means the first parent of + that commit object. '{caret}<n>' means the <n>th parent (i.e. + 'rev{caret}' + is equivalent to 'rev{caret}1'). As a special rule, + 'rev{caret}0' means the commit itself and is used when 'rev' is the + object name of a tag object that refers to a commit object. + +* A suffix '{tilde}<n>' to a revision parameter means the commit + object that is the <n>th generation grand-parent of the named + commit object, following only the first parent. I.e. rev~3 is + equivalent to rev{caret}{caret}{caret} which is equivalent to + rev{caret}1{caret}1{caret}1. See below for a illustration of + the usage of this form. + +* A suffix '{caret}' followed by an object type name enclosed in + brace pair (e.g. `v0.99.8{caret}\{commit\}`) means the object + could be a tag, and dereference the tag recursively until an + object of that type is found or the object cannot be + dereferenced anymore (in which case, barf). `rev{caret}0` + introduced earlier is a short-hand for `rev{caret}\{commit\}`. + +* A suffix '{caret}' followed by an empty brace pair + (e.g. `v0.99.8{caret}\{\}`) means the object could be a tag, + and dereference the tag recursively until a non-tag object is + found. + +* A colon, followed by a slash, followed by a text: this names + a commit whose commit message starts with the specified text. + This name returns the youngest matching commit which is + reachable from any ref. If the commit message starts with a + '!', you have to repeat that; the special sequence ':/!', + followed by something else than '!' is reserved for now. + +* A suffix ':' followed by a path; this names the blob or tree + at the given path in the tree-ish object named by the part + before the colon. + +* A colon, optionally followed by a stage number (0 to 3) and a + colon, followed by a path; this names a blob object in the + index at the given path. Missing stage number (and the colon + that follows it) names a stage 0 entry. During a merge, stage + 1 is the common ancestor, stage 2 is the target branch's version + (typically the current branch), and stage 3 is the version from + the branch being merged. + +Here is an illustration, by Jon Loeliger. Both commit nodes B +and C are parents of commit node A. Parent commits are ordered +left-to-right. + +........................................ +G H I J + \ / \ / + D E F + \ | / \ + \ | / | + \|/ | + B C + \ / + \ / + A +........................................ + + A = = A^0 + B = A^ = A^1 = A~1 + C = A^2 = A^2 + D = A^^ = A^1^1 = A~2 + E = B^2 = A^^2 + F = B^3 = A^^3 + G = A^^^ = A^1^1^1 = A~3 + H = D^2 = B^^2 = A^^^2 = A~2^2 + I = F^ = B^3^ = A^^3^ + J = F^2 = B^3^2 = A^^3^2 + + +SPECIFYING RANGES +----------------- + +History traversing commands such as 'git log' operate on a set +of commits, not just a single commit. To these commands, +specifying a single revision with the notation described in the +previous section means the set of commits reachable from that +commit, following the commit ancestry chain. + +To exclude commits reachable from a commit, a prefix `{caret}` +notation is used. E.g. `{caret}r1 r2` means commits reachable +from `r2` but exclude the ones reachable from `r1`. + +This set operation appears so often that there is a shorthand +for it. When you have two commits `r1` and `r2` (named according +to the syntax explained in SPECIFYING REVISIONS above), you can ask +for commits that are reachable from r2 excluding those that are reachable +from r1 by `{caret}r1 r2` and it can be written as `r1..r2`. + +A similar notation `r1\...r2` is called symmetric difference +of `r1` and `r2` and is defined as +`r1 r2 --not $(git merge-base --all r1 r2)`. +It is the set of commits that are reachable from either one of +`r1` or `r2` but not from both. + +Two other shorthands for naming a set that is formed by a commit +and its parent commits exist. The `r1{caret}@` notation means all +parents of `r1`. `r1{caret}!` includes commit `r1` but excludes +all of its parents. + +Here are a handful of examples: + + D G H D + D F G H I J D F + ^G D H D + ^D B E I J F B + B...C G H D E B C + ^D B C E I J F B C + C^@ I J F + F^! D G H D F + +PARSEOPT +-------- + +In `--parseopt` mode, 'git rev-parse' helps massaging options to bring to shell +scripts 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 and +understand, and echoes on the standard output a line suitable for `sh(1)` `eval` +to replace the arguments with normalized ones. In case of error, it outputs +usage on the standard error stream, and exits with code 129. + +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 more than one) are used for the usage. +The lines after the separator describe the options. + +Each line of options has this format: + +------------ +<opt_spec><flags>* SP+ help LF +------------ + +`<opt_spec>`:: + its format is the short option character, then the long option name + separated by a comma. Both parts are not required, though at least one + is necessary. `h,help`, `dry-run` and `f` are all three correct + `<opt_spec>`. + +`<flags>`:: + `<flags>` are of `*`, `=`, `?` or `!`. + * Use `=` if the option takes an argument. + + * Use `?` to mean that the option is optional (though its use is discouraged). + + * Use `*` to mean that this option should not be listed in the usage + generated for the `-h` argument. It's shown for `--help-all` as + documented in linkgit:gitcli[7]. + + * Use `!` to not make the corresponding negated long option available. + +The remainder of the line, after stripping the spaces, is used +as the help associated to the option. + +Blank lines are ignored, and lines that don't match this specification are used +as option group headers (start the line with a space to create such +lines on purpose). + +Example +~~~~~~~ + +------------ +OPTS_SPEC="\ +some-command [options] <args>... + +some-command does foo and bar! +-- +h,help show the help + +foo some nifty option --foo +bar= some cool option --bar with an argument + + An option group Header +C? option C with an optional argument" + +eval `echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?` +------------ + +SQ-QUOTE +-------- + +In `--sq-quote` mode, 'git rev-parse' echoes on the standard output a +single line suitable for `sh(1)` `eval`. This line is made by +normalizing the arguments following `--sq-quote`. Nothing other than +quoting the arguments is done. + +If you want command input to still be interpreted as usual by +'git rev-parse' before the output is shell quoted, see the `--sq` +option. + +Example +~~~~~~~ + +------------ +$ cat >your-git-script.sh <<\EOF +#!/bin/sh +args=$(git rev-parse --sq-quote "$@") # quote user-supplied arguments +command="git frotz -n24 $args" # and use it inside a handcrafted + # command line +eval "$command" +EOF + +$ sh your-git-script.sh "a b'c" +------------ + +EXAMPLES +-------- + +* Print the object name of the current commit: ++ +------------ +$ git rev-parse --verify HEAD +------------ + +* Print the commit object name from the revision in the $REV shell variable: ++ +------------ +$ git rev-parse --verify $REV +------------ ++ +This will error out if $REV is empty or not a valid revision. + +* Same as above: ++ +------------ +$ git rev-parse --default master --verify $REV +------------ ++ +but if $REV is empty, the commit object name from master will be printed. + + +Author +------ +Written by Linus Torvalds <torvalds@osdl.org> . +Junio C Hamano <gitster@pobox.com> and Pierre Habouzit <madcoder@debian.org> + +Documentation +-------------- +Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. + +GIT +--- +Part of the linkgit:git[1] suite |