git-merge-file.adoc

git-merge-file(1)
=================

NAME
----
git-merge-file - Run a three-way file merge


SYNOPSIS
--------
[verse]
'git merge-file' [-L <current-name> [-L <base-name> [-L <other-name>]]]
	[--ours|--theirs|--union] [-p|--stdout] [-q|--quiet] [--marker-size=<n>]
	[--[no-]diff3] [--object-id] <current> <base> <other>


DESCRIPTION
-----------
Given three files `<current>`, `<base>` and `<other>`,
'git merge-file' incorporates all changes that lead from `<base>`
to `<other>` into `<current>`. The result ordinarily goes into
`<current>`. 'git merge-file' is useful for combining separate changes
to an original. Suppose `<base>` is the original, and both
`<current>` and `<other>` are modifications of `<base>`,
then 'git merge-file' combines both changes.

A conflict occurs if both `<current>` and `<other>` have changes
in a common segment of lines. If a conflict is found, 'git merge-file'
normally outputs a warning and brackets the conflict with lines containing
<<<<<<< and >>>>>>> markers. A typical conflict will look like this:

	<<<<<<< A
	lines in file A
	=======
	lines in file B
	>>>>>>> B

If there are conflicts, the user should edit the result and delete one of
the alternatives.  When `--ours`, `--theirs`, or `--union` option is in effect,
however, these conflicts are resolved favouring lines from `<current>`,
lines from `<other>`, or lines from both respectively.  The length of the
conflict markers can be given with the `--marker-size` option.

If `--object-id` is specified, exactly the same behavior occurs, except that
instead of specifying what to merge as files, it is specified as a list of
object IDs referring to blobs.

The exit value of this program is negative on error, and the number of
conflicts otherwise (truncated to 127 if there are more than that many
conflicts). If the merge was clean, the exit value is 0.

'git merge-file' is designed to be a minimal clone of RCS 'merge'; that is, it
implements all of RCS 'merge''s functionality which is needed by
linkgit:git[1].


OPTIONS
-------

--object-id::
	Specify the contents to merge as blobs in the current repository instead of
	files.  In this case, the operation must take place within a valid repository.
+
If the `-p` option is specified, the merged file (including conflicts, if any)
goes to standard output as normal; otherwise, the merged file is written to the
object store and the object ID of its blob is written to standard output.

-L <label>::
	This option may be given up to three times, and
	specifies labels to be used in place of the
	corresponding file names in conflict reports. That is,
	`git merge-file -L x -L y -L z a b c` generates output that
	looks like it came from files x, y and z instead of
	from files a, b and c.

-p::
	Send results to standard output instead of overwriting
	`<current>`.

-q::
	Quiet; do not warn about conflicts.

--diff3::
	Show conflicts in "diff3" style.

--zdiff3::
	Show conflicts in "zdiff3" style.

--ours::
--theirs::
--union::
	Instead of leaving conflicts in the file, resolve conflicts
	favouring our (or their or both) side of the lines.

--diff-algorithm={patience|minimal|histogram|myers}::
	Use a different diff algorithm while merging. The current default is "myers",
	but selecting more recent algorithm such as "histogram" can help
	avoid mismerges that occur due to unimportant matching lines
	(such as braces from distinct functions). See also
	linkgit:git-diff[1] `--diff-algorithm`.

EXAMPLES
--------

`git merge-file README.my README README.upstream`::

	combines the changes of README.my and README.upstream since README,
	tries to merge them and writes the result into README.my.

`git merge-file -L a -L b -L c tmp/a123 tmp/b234 tmp/c345`::

	merges tmp/a123 and tmp/c345 with the base tmp/b234, but uses labels
	`a` and `c` instead of `tmp/a123` and `tmp/c345`.

`git merge-file -p --object-id abc1234 def567 890abcd`::

	combines the changes of the blob abc1234 and 890abcd since def567,
	tries to merge them and writes the result to standard output

GIT
---
Part of the linkgit:git[1] suite