| SPECIFYING REVISIONS |
| -------------------- |
| |
| A revision parameter '<rev>' typically, but not necessarily, names a |
| commit object. It uses what is called an 'extended SHA-1' |
| syntax. Here are various ways to spell object names. The |
| ones listed near the end of this list name trees and |
| blobs contained in a commit. |
| |
| '<sha1>', e.g. 'dae86e1950b1277e545cee180551750029cfe735', 'dae86e':: |
| The full SHA-1 object name (40-byte hexadecimal string), or |
| a leading substring that is unique within the repository. |
| E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both |
| name the same commit object if there is no other object in |
| your repository whose object name starts with dae86e. |
| |
| '<describeOutput>', e.g. 'v1.7.4.2-679-g3bee7fb':: |
| 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. |
| |
| '<refname>', e.g. 'master', 'heads/master', 'refs/heads/master':: |
| 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 '<refname>' is disambiguated by taking the |
| first match in the following rules: |
| |
| . If '$GIT_DIR/<refname>' exists, that is what you mean (this is usually |
| useful only for `HEAD`, `FETCH_HEAD`, `ORIG_HEAD`, `MERGE_HEAD` |
| and `CHERRY_PICK_HEAD`); |
| |
| . otherwise, 'refs/<refname>' if it exists; |
| |
| . otherwise, 'refs/tags/<refname>' if it exists; |
| |
| . otherwise, 'refs/heads/<refname>' if it exists; |
| |
| . otherwise, 'refs/remotes/<refname>' if it exists; |
| |
| . otherwise, 'refs/remotes/<refname>/HEAD' if it exists. |
| + |
| `HEAD` names the commit on which you based the changes in the working tree. |
| `FETCH_HEAD` records the branch which you fetched from a remote repository |
| with your last `git fetch` invocation. |
| `ORIG_HEAD` is created by commands that move your `HEAD` in a drastic |
| way, to record the position of the `HEAD` before their operation, so that |
| you can easily change the tip of the branch back to the state before you ran |
| them. |
| `MERGE_HEAD` records the commit(s) which you are merging into your branch |
| when you run `git merge`. |
| `CHERRY_PICK_HEAD` records the commit which you are cherry-picking |
| when you run `git cherry-pick`. |
| + |
| Note that any of the 'refs/*' cases above may come either from |
| the '$GIT_DIR/refs' directory or from the '$GIT_DIR/packed-refs' file. |
| While the ref name encoding is unspecified, UTF-8 is preferred as |
| some output processing may assume ref names in UTF-8. |
| |
| '@':: |
| '@' alone is a shortcut for `HEAD`. |
| |
| '<refname>@{<date>}', e.g. 'master@\{yesterday\}', 'HEAD@{5 minutes ago}':: |
| A ref followed by the suffix '@' with a date specification |
| enclosed in a brace |
| pair (e.g. '\{yesterday\}', '{1 month 2 weeks 3 days 1 hour 1 |
| second ago}' or '{1979-02-26 18:30:00}') specifies the value |
| of the ref at a prior point in time. This suffix may only be |
| used immediately following a ref name and the ref must have an |
| existing log ('$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`. |
| |
| '<refname>@{<n>}', e.g. 'master@\{1\}':: |
| A ref followed by the suffix '@' with an ordinal specification |
| enclosed in a brace pair (e.g. '\{1\}', '\{15\}') specifies |
| 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/<refname>'). |
| |
| '@{<n>}', e.g. '@\{1\}':: |
| You can use the '@' construct with an empty ref part to get at a |
| reflog entry of the current branch. For example, if you are on |
| branch 'blabla' then '@\{1\}' means the same as 'blabla@\{1\}'. |
| |
| '@{-<n>}', e.g. '@{-1}':: |
| The construct '@{-<n>}' means the <n>th branch/commit checked out |
| before the current one. |
| |
| '<branchname>@\{upstream\}', e.g. 'master@\{upstream\}', '@\{u\}':: |
| The suffix '@\{upstream\}' to a branchname (short form '<branchname>@\{u\}') |
| refers to the branch that the branch specified by branchname is set to build on |
| top of (configured with `branch.<name>.remote` and |
| `branch.<name>.merge`). A missing branchname defaults to the |
| current one. |
| |
| '<branchname>@\{push\}', e.g. 'master@\{push\}', '@\{push\}':: |
| The suffix '@\{push}' reports the branch "where we would push to" if |
| `git push` were run while `branchname` was checked out (or the current |
| `HEAD` if no branchname is specified). Since our push destination is |
| in a remote repository, of course, we report the local tracking branch |
| that corresponds to that branch (i.e., something in 'refs/remotes/'). |
| + |
| Here's an example to make it more clear: |
| + |
| ------------------------------ |
| $ git config push.default current |
| $ git config remote.pushdefault myfork |
| $ git checkout -b mybranch origin/master |
| |
| $ git rev-parse --symbolic-full-name @{upstream} |
| refs/remotes/origin/master |
| |
| $ git rev-parse --symbolic-full-name @{push} |
| refs/remotes/myfork/mybranch |
| ------------------------------ |
| + |
| Note in the example that we set up a triangular workflow, where we pull |
| from one location and push to another. In a non-triangular workflow, |
| '@\{push}' is the same as '@\{upstream}', and there is no need for it. |
| |
| '<rev>{caret}', e.g. 'HEAD{caret}, v1.5.1{caret}0':: |
| 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. |
| |
| '<rev>{tilde}<n>', e.g. 'master{tilde}3':: |
| A suffix '{tilde}<n>' to a revision parameter means the commit |
| object that is the <n>th generation ancestor of the named |
| commit object, following only the first parents. I.e. '<rev>{tilde}3' is |
| equivalent to '<rev>{caret}{caret}{caret}' which is equivalent to |
| '<rev>{caret}1{caret}1{caret}1'. See below for an illustration of |
| the usage of this form. |
| |
| '<rev>{caret}{<type>}', e.g. 'v0.99.8{caret}\{commit\}':: |
| A suffix '{caret}' followed by an object type name enclosed in |
| brace pair means dereference the object at '<rev>' recursively until |
| an object of type '<type>' is found or the object cannot be |
| dereferenced anymore (in which case, barf). |
| For example, if '<rev>' is a commit-ish, '<rev>{caret}\{commit\}' |
| describes the corresponding commit object. |
| Similarly, if '<rev>' is a tree-ish, '<rev>{caret}\{tree\}' |
| describes the corresponding tree object. |
| '<rev>{caret}0' |
| is a short-hand for '<rev>{caret}\{commit\}'. |
| + |
| 'rev{caret}\{object\}' can be used to make sure 'rev' names an |
| object that exists, without requiring 'rev' to be a tag, and |
| without dereferencing 'rev'; because a tag is already an object, |
| it does not have to be dereferenced even once to get to an object. |
| + |
| 'rev{caret}\{tag\}' can be used to ensure that 'rev' identifies an |
| existing tag object. |
| |
| '<rev>{caret}{}', e.g. 'v0.99.8{caret}{}':: |
| A suffix '{caret}' followed by an empty brace pair |
| means the object could be a tag, |
| and dereference the tag recursively until a non-tag object is |
| found. |
| |
| '<rev>{caret}{/<text>}', e.g. 'HEAD^{/fix nasty bug}':: |
| A suffix '{caret}' to a revision parameter, followed by a brace |
| pair that contains a text led by a slash, |
| is the same as the ':/fix nasty bug' syntax below except that |
| it returns the youngest matching commit which is reachable from |
| the '<rev>' before '{caret}'. |
| |
| ':/<text>', e.g. ':/fix nasty bug':: |
| A colon, followed by a slash, followed by a text, names |
| a commit whose commit message matches the specified regular expression. |
| This name returns the youngest matching commit which is |
| reachable from any ref. The regular expression can match any part of the |
| commit message. To match messages starting with a string, one can use |
| e.g. ':/^foo'. The special sequence ':/!' is reserved for modifiers to what |
| is matched. ':/!-foo' performs a negative match, while ':/!!foo' matches a |
| literal '!' character, followed by 'foo'. Any other sequence beginning with |
| ':/!' is reserved for now. |
| |
| '<rev>:<path>', e.g. 'HEAD:README', ':README', 'master:./README':: |
| A suffix ':' followed by a path names the blob or tree |
| at the given path in the tree-ish object named by the part |
| before the colon. |
| ':path' (with an empty part before the colon) |
| is a special case of the syntax described next: content |
| recorded in the index at the given path. |
| A path starting with './' or '../' is relative to the current working directory. |
| The given path will be converted to be relative to the working tree's root directory. |
| This is most useful to address a blob or tree from a commit or tree that has |
| the same tree structure as the working tree. |
| |
| ':<n>:<path>', e.g. ':0:README', ':README':: |
| A colon, optionally followed by a stage number (0 to 3) and a |
| colon, followed by a path, names a blob object in the |
| index at the given path. A 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 which is 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. |
| |
| In these two shorthands, you can omit one end and let it default to HEAD. |
| For example, 'origin..' is a shorthand for 'origin..HEAD' and asks "What |
| did I do since I forked from the origin branch?" Similarly, '..origin' |
| is a shorthand for 'HEAD..origin' and asks "What did the origin do since |
| I forked from them?" Note that '..' would mean 'HEAD..HEAD' which is an |
| empty range that is both reachable and unreachable from HEAD. |
| |
| 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. |
| |
| To summarize: |
| |
| '<rev>':: |
| Include commits that are reachable from (i.e. ancestors of) |
| <rev>. |
| |
| '{caret}<rev>':: |
| Exclude commits that are reachable from (i.e. ancestors of) |
| <rev>. |
| |
| '<rev1>..<rev2>':: |
| Include commits that are reachable from <rev2> but exclude |
| those that are reachable from <rev1>. When either <rev1> or |
| <rev2> is omitted, it defaults to `HEAD`. |
| |
| '<rev1>\...<rev2>':: |
| Include commits that are reachable from either <rev1> or |
| <rev2> but exclude those that are reachable from both. When |
| either <rev1> or <rev2> is omitted, it defaults to `HEAD`. |
| |
| '<rev>{caret}@', e.g. 'HEAD{caret}@':: |
| A suffix '{caret}' followed by an at sign is the same as listing |
| all parents of '<rev>' (meaning, include anything reachable from |
| its parents, but not the commit itself). |
| |
| '<rev>{caret}!', e.g. 'HEAD{caret}!':: |
| A suffix '{caret}' followed by an exclamation mark is the same |
| as giving commit '<rev>' and then all its parents prefixed with |
| '{caret}' to exclude them (and their ancestors). |
| |
| 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 C |
| B...C G H D E B C |
| ^D B C E I J F B C |
| C I J F C |
| C^@ I J F |
| C^! C |
| F^! D G H D F |