DESCRIPTION
-----------
-Many git Porcelainish commands take mixture of flags
+Many git porcelainish commands take mixture of flags
(i.e. parameters that begin with a dash '-') and parameters
meant for underlying `git-rev-list` command they use internally
and flags and parameters for other commands they use as the
--short, --short=number::
Instead of outputting the full SHA1 values of object names try to
- abbriviate them to a shorter unique name. When no length is specified
+ abbreviate them to a shorter unique name. When no length is specified
7 is used. The minimum length is 4.
--since=datestring, --after=datestring::
A revision parameter typically, but not necessarily, names a
commit object. They use what is called an 'extended SHA1'
-syntax.
+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.
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, 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` 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;
-* A suffix '@' followed by a date specification enclosed in a brace
+ . otherwise, `$GIT_DIR/refs/remotes/<name>/HEAD` if exists.
+
+* A ref followed by the suffix '@' with a date specification
+ enclosed in a brace
pair (e.g. '\{yesterday\}', '\{1 month 2 weeks 3 days 1 hour 1
second ago\}' or '\{1979-02-26 18:30:00\}') to specify the value
of the ref at a prior point in time. This suffix may only be
used immediately following a ref name and the ref must have an
existing log ($GIT_DIR/logs/<ref>).
+* 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\}'.
+
* 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}'
'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 '~<n>' to a revision parameter means the commit
+* 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.
+ 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
and dereference the tag recursively until a non-tag object is
found.
-'git-rev-parse' also accepts a prefix '{caret}' to revision parameter,
-which is passed to 'git-rev-list'. Two revision parameters
-concatenated with '..' is a short-hand for writing a range
-between them. I.e. 'r1..r2' is equivalent to saying '{caret}r1 r2'
+* 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 an stage 0 entry.
Here is an illustration, by Jon Loeliger. Both node B and C are
a commit parents of commit node A. Parent commits are ordered
G H I J
\ / \ /
D E F
- \ | /
- \ | /
- \|/
+ \ | / \
+ \ | / |
+ \|/ |
B C
\ /
\ /
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. "`r1..r2`" is equivalent to "`{caret}r1 r2`". It is
+the difference of two sets (subtract the set of commits
+reachable from `r1` from the set of commits reachable from
+`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 it 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 exists. `r1{caret}@` notation means all
+parents of `r1`. `r1{caret}!` includes commit `r1` but excludes
+its all parents.
+
+Here are a handful examples:
+
+ D A B D
+ D F A B C D F
+ ^A G B D
+ ^A F B C F
+ G...I C D F G I
+ ^B G I C D F G I
+ F^@ A B C
+ F^! H D F H
+
Author
------
Written by Linus Torvalds <torvalds@osdl.org> and