glossary: explain "master" and "origin"

[git.git] / Documentation / pull-fetch-param.txt

diff --git a/Documentation/pull-fetch-param.txt b/Documentation/pull-fetch-param.txt
index 51222b6..b5b9792 100644 (file)
--- a/Documentation/pull-fetch-param.txt
+++ b/Documentation/pull-fetch-param.txt
@@ -1,87 +1,144 @@
 <repository>::
 <repository>::

-       The "remote" repository to pull from.  One of the
-       following notations can be used to name the repository
-       to pull from:
+       The "remote" repository that is the source of a fetch
+       or pull operation, or the destination of a push operation.
+       One of the following notations can be used
+       to name the remote repository:

 +
 ===============================================================
 +
 ===============================================================

-- Rsync URL:           rsync://remote.machine/path/to/repo.git/
-- HTTP(s) URL:         http://remote.machine/path/to/repo.git/
-- git URL:             git://remote.machine/path/to/repo.git/
-                       or remote.machine:/path/to/repo.git/
-- Local directory:     /path/to/repo.git/
+- rsync://host.xz/path/to/repo.git/
+- http://host.xz/path/to/repo.git/
+- https://host.xz/path/to/repo.git/
+- git://host.xz/path/to/repo.git/
+- git://host.xz/~user/path/to/repo.git/
+- ssh://host.xz/path/to/repo.git/
+- ssh://host.xz/~user/path/to/repo.git/
+- ssh://host.xz/~/path/to/repo.git
+===============================================================
++
+SSH Is the default transport protocol and also supports an
+scp-like syntax.  Both syntaxes support username expansion,
+as does the native git protocol. The following three are
+identical to the last three above, respectively:
++
+===============================================================
+- host.xz:/path/to/repo.git/
+- host.xz:~user/path/to/repo.git/
+- host.xz:path/to/repo.git
+===============================================================
++
+To sync with a local directory, use:
++
+===============================================================
+- /path/to/repo.git/

 ===============================================================
 +
 In addition to the above, as a short-hand, the name of a
 ===============================================================
 +
 In addition to the above, as a short-hand, the name of a

-file in $GIT_DIR/remotes directory can be given; the
+file in `$GIT_DIR/remotes` directory can be given; the

 named file should be in the following format:
 +
        URL: one of the above URL format
 named file should be in the following format:
 +
        URL: one of the above URL format

-       Push: <refspec>...
-       Pull: <refspec>...
+       Push: <refspec>
+       Pull: <refspec>

 +
 When such a short-hand is specified in place of
 <repository> without <refspec> parameters on the command
 +
 When such a short-hand is specified in place of
 <repository> without <refspec> parameters on the command

-line, <refspec>... specified on Push lines or Pull lines
-are used for "git push" and "git fetch/pull",
-respectively.
+line, <refspec> specified on `Push:` lines or `Pull:`
+lines are used for `git-push` and `git-fetch`/`git-pull`,
+respectively.  Multiple `Push:` and and `Pull:` lines may
+be specified for additional branch mappings.

 +
 +

-The name of a file in $GIT_DIR/branches directory can be
+The name of a file in `$GIT_DIR/branches` directory can be

 specified as an older notation short-hand; the named
 file should contain a single line, a URL in one of the
 specified as an older notation short-hand; the named
 file should contain a single line, a URL in one of the

-above formats, optionally followed by a hash '#' and the
+above formats, optionally followed by a hash `#` and the

 name of remote head (URL fragment notation).
 name of remote head (URL fragment notation).

-$GIT_DIR/branches/<remote> file that stores a <url>
+`$GIT_DIR/branches/<remote>` file that stores a <url>

 without the fragment is equivalent to have this in the
 without the fragment is equivalent to have this in the

-corresponding file in the $GIT_DIR/remotes/ directory
+corresponding file in the `$GIT_DIR/remotes/` directory.

 +
        URL: <url>
        Pull: refs/heads/master:<remote>
 +
 +
        URL: <url>
        Pull: refs/heads/master:<remote>
 +

-while having <url>#<head> is equivalent to
+while having `<url>#<head>` is equivalent to

 +
        URL: <url>
        Pull: refs/heads/<head>:<remote>
 
 <refspec>::
        The canonical format of a <refspec> parameter is
 +
        URL: <url>
        Pull: refs/heads/<head>:<remote>
 
 <refspec>::
        The canonical format of a <refspec> parameter is

-       '+?<src>:<dst>'; that is, an optional plus '+', followed
-       by the source ref, followed by a colon ':', followed by
+       `+?<src>:<dst>`; that is, an optional plus `+`, followed
+       by the source ref, followed by a colon `:`, followed by

        the destination ref.
 +
        the destination ref.
 +

-When used in "git push", the <src> side can be an
+When used in `git-push`, the <src> side can be an

 arbitrary "SHA1 expression" that can be used as an
 arbitrary "SHA1 expression" that can be used as an

-argument to "git-cat-file -t".  E.g. "master~4" (push
+argument to `git-cat-file -t`.  E.g. `master~4` (push

 four parents before the current master head).
 +
 four parents before the current master head).
 +

-For "git push", the local ref that matches <src> is used
+For `git-push`, the local ref that matches <src> is used

 to fast forward the remote ref that matches <dst>.  If
 to fast forward the remote ref that matches <dst>.  If

-the optional plus '+' is used, the remote ref is updated
+the optional plus `+` is used, the remote ref is updated

 even if it does not result in a fast forward update.
 +
 even if it does not result in a fast forward update.
 +

-For "git fetch/pull", the remote ref that matches <src>
+For `git-fetch` and `git-pull`, the remote ref that matches <src>

 is fetched, and if <dst> is not empty string, the local
 ref that matches it is fast forwarded using <src>.
 is fetched, and if <dst> is not empty string, the local
 ref that matches it is fast forwarded using <src>.

-Again, if the optional plus '+' is used, the local ref
+Again, if the optional plus `+` is used, the local ref

 is updated even if it does not result in a fast forward
 update.
 +
 is updated even if it does not result in a fast forward
 update.
 +

+[NOTE]
+If the remote branch from which you want to pull is
+modified in non-linear ways such as being rewound and
+rebased frequently, then a pull will attempt a merge with
+an older version of itself, likely conflict, and fail.
+It is under these conditions that you would want to use
+the `+` sign to indicate non-fast-forward updates will
+be needed.  There is currently no easy way to determine
+or declare that a branch will be made available in a
+repository with this behavior; the pulling user simply
+must know this is the expected usage pattern for a branch.
++
+[NOTE]
+You never do your own development on branches that appear
+on the right hand side of a <refspec> colon on `Pull:` lines;
+they are to be updated by `git-fetch`.  If you intend to do
+development derived from a remote branch `B`, have a `Pull:`
+line to track it (i.e. `Pull: B:remote-B`), and have a separate
+branch `my-B` to do your development on top of it.  The latter
+is created by `git branch my-B remote-B` (or its equivalent `git
+checkout -b my-B remote-B`).  Run `git fetch` to keep track of
+the progress of the remote side, and when you see something new
+on the remote branch, merge it into your development branch with
+`git pull . remote-B`, while you are on `my-B` branch.
+The common `Pull: master:origin` mapping of a remote `master`
+branch to a local `origin` branch, which is then merged to a
+local development branch, again typically named `master`, is made
+when you run `git clone` for you to follow this pattern.
++
+[NOTE]
+There is a difference between listing multiple <refspec>
+directly on `git-pull` command line and having multiple
+`Pull:` <refspec> lines for a <repository> and running
+`git-pull` command without any explicit <refspec> parameters.
+<refspec> listed explicitly on the command line are always
+merged into the current branch after fetching.  In other words,
+if you list more than one remote refs, you would be making
+an Octopus.  While `git-pull` run without any explicit <refspec>
+parameter takes default <refspec>s from `Pull:` lines, it
+merges only the first <refspec> found into the current branch,
+after fetching all the remote refs.  This is because making an
+Octopus from remote refs is rarely done, while keeping track
+of multiple remote heads in one-go by fetching more than one
+is often useful.
++

 Some short-cut notations are also supported.
 +
 Some short-cut notations are also supported.
 +

-* For backward compatibility, "tag" is almost ignored;
+* For backward compatibility, `tag` is almost ignored;

   it just makes the following parameter <tag> to mean a
   it just makes the following parameter <tag> to mean a

-  refspec "refs/tags/<tag>:refs/tags/<tag>".
+  refspec `refs/tags/<tag>:refs/tags/<tag>`.

 * A parameter <ref> without a colon is equivalent to
 * A parameter <ref> without a colon is equivalent to

-  <ref>: when pulling/fetching, and <ref>:<ref> when
+  <ref>: when pulling/fetching, and <ref>`:`<ref> when

   pushing.  That is, do not store it locally if
   fetching, and update the same name if pushing.
 
   pushing.  That is, do not store it locally if
   fetching, and update the same name if pushing.
 

--a, \--append::
-       Append ref names and object names of fetched refs to the
-       existing contents of $GIT_DIR/FETCH_HEAD.  Without this
-       option old data in $GIT_DIR/FETCH_HEAD will be overwritten.
-
--f, \--force::
-       Usually, the command refuses to update a local ref that is
-       not an ancestor of the remote ref used to overwrite it.
-       This flag disables the check.  What this means is that the
-       local repository can lose commits; use it with care.