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Diffstat (limited to 'Documentation/git-rev-parse.txt')
| -rw-r--r-- | Documentation/git-rev-parse.txt | 204 |
1 files changed, 6 insertions, 198 deletions
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt index 8db600f6ba..be4c053360 100644 --- a/Documentation/git-rev-parse.txt +++ b/Documentation/git-rev-parse.txt @@ -174,202 +174,7 @@ shown. If the pattern does not contain a globbing character (`?`, 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 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 `$GIT_DIR/<name>` exists, that is what you mean (this is usually - useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD` and `MERGE_HEAD`); - - . otherwise, `refs/<name>` if exists; - - . otherwise, `refs/tags/<name>` if exists; - - . otherwise, `refs/heads/<name>` if exists; - - . otherwise, `refs/remotes/<name>` if exists; - - . otherwise, `refs/remotes/<name>/HEAD` if exists. -+ -HEAD names the commit your changes in the working tree is based on. -FETCH_HEAD records the branch you fetched from a remote repository -with your last 'git fetch' invocation. -ORIG_HEAD is created by commands that moves your HEAD in a drastic -way, to record the position of the HEAD before their operation, so that -you can change the tip of the branch back to the state before you ran -them easily. -MERGE_HEAD records the commit(s) you are merging into your branch -when you run 'git merge'. -+ -Note that any of the `refs/*` cases above may come either from -the `$GIT_DIR/refs` directory or from the `$GIT_DIR/packed-refs` file. - -* A ref followed by the suffix '@' with a date specification - enclosed in a brace - pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1 - second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value - of the ref at a prior point in time. This suffix may only be - used immediately following a ref name and the ref must have an - existing log ($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 $(git merge-base --all r1 r2)`. -It is the set of commits that are reachable from either one of -`r1` or `r2` but not from both. - -Two other shorthands for naming a set that is formed by a commit -and its parent commits exist. The `r1{caret}@` notation means all -parents of `r1`. `r1{caret}!` includes commit `r1` but excludes -all of its parents. - -Here are a handful of examples: - - D G H D - D F G H I J D F - ^G D H D - ^D B E I J F B - B...C G H D E B C - ^D B C E I J F B C - C^@ I J F - F^! D G H D F +include::revisions.txt[] PARSEOPT -------- @@ -379,10 +184,13 @@ scripts the same facilities C builtins have. It works as an option normalizer (e.g. splits single switches aggregate values), a bit like `getopt(1)` does. It takes on the standard input the specification of the options to parse and -understand, and echoes on the standard output a line suitable for `sh(1)` `eval` +understand, and echoes on the standard output a string suitable for `sh(1)` `eval` to replace the arguments with normalized ones. In case of error, it outputs usage on the standard error stream, and exits with code 129. +Note: Make sure you quote the result when passing it to `eval`. See +below for an example. + Input Format ~~~~~~~~~~~~ @@ -439,7 +247,7 @@ bar= some cool option --bar with an argument An option group Header C? option C with an optional argument" -eval `echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?` +eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)" ------------ SQ-QUOTE |