git-merge-file(1) [centos man page]

GIT-MERGE-FILE(1)						    Git Manual							 GIT-MERGE-FILE(1)

NAME

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

SYNOPSIS

       git merge-file [-L <current-name> [-L <base-name> [-L <other-name>]]]
	       [--ours|--theirs|--union] [-p|--stdout] [-q|--quiet] [--marker-size=<n>]
	       <current-file> <base-file> <other-file>

DESCRIPTION

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

       A conflict occurs if both <current-file> and <other-file> 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-file>, lines from <other-file>, or lines from both
       respectively. The length of the conflict markers can be given with the --marker-size option.

       The exit value of this program is negative on error, and the number of conflicts otherwise. 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
       git(1).

OPTIONS

       -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-file>.

       -q
	   Quiet; do not warn about conflicts.

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

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

       Part of the git(1) suite

Git 1.8.3.1							    06/10/2014							 GIT-MERGE-FILE(1)

GIT-MERGE-BASE(1)						    Git Manual							 GIT-MERGE-BASE(1)

NAME

       git-merge-base - Find as good common ancestors as possible for a merge

SYNOPSIS

       git merge-base [-a|--all] <commit> <commit>...
       git merge-base [-a|--all] --octopus <commit>...
       git merge-base --is-ancestor <commit> <commit>
       git merge-base --independent <commit>...

DESCRIPTION

       git merge-base finds best common ancestor(s) between two commits to use in a three-way merge. One common ancestor is better than another
       common ancestor if the latter is an ancestor of the former. A common ancestor that does not have any better common ancestor is a best
       common ancestor, i.e. a merge base. Note that there can be more than one merge base for a pair of commits.

OPERATION MODE

       As the most common special case, specifying only two commits on the command line means computing the merge base between the given two
       commits.

       More generally, among the two commits to compute the merge base from, one is specified by the first commit argument on the command line;
       the other commit is a (possibly hypothetical) commit that is a merge across all the remaining commits on the command line.

       As a consequence, the merge base is not necessarily contained in each of the commit arguments if more than two commits are specified. This
       is different from git-show-branch(1) when used with the --merge-base option.

       --octopus
	   Compute the best common ancestors of all supplied commits, in preparation for an n-way merge. This mimics the behavior of git
	   show-branch --merge-base.

       --independent
	   Instead of printing merge bases, print a minimal subset of the supplied commits with the same ancestors. In other words, among the
	   commits given, list those which cannot be reached from any other. This mimics the behavior of git show-branch --independent.

       --is-ancestor
	   Check if the first <commit> is an ancestor of the second <commit>, and exit with status 0 if true, or with status 1 if not. Errors are
	   signaled by a non-zero status that is not 1.

OPTIONS

       -a, --all
	   Output all merge bases for the commits, instead of just one.

DISCUSSION

       Given two commits A and B, git merge-base A B will output a commit which is reachable from both A and B through the parent relationship.

       For example, with this topology:

		    o---o---o---B
		   /
	   ---o---1---o---o---o---A

       the merge base between A and B is 1.

       Given three commits A, B and C, git merge-base A B C will compute the merge base between A and a hypothetical commit M, which is a merge
       between B and C. For example, with this topology:

		  o---o---o---o---C
		 /
		/   o---o---o---B
	       /   /
	   ---2---1---o---o---o---A

       the result of git merge-base A B C is 1. This is because the equivalent topology with a merge commit M between B and C is:

		  o---o---o---o---o
		 /		   
		/   o---o---o---o---M
	       /   /
	   ---2---1---o---o---o---A

       and the result of git merge-base A M is 1. Commit 2 is also a common ancestor between A and M, but 1 is a better common ancestor, because 2
       is an ancestor of 1. Hence, 2 is not a merge base.

       The result of git merge-base --octopus A B C is 2, because 2 is the best common ancestor of all commits.

       When the history involves criss-cross merges, there can be more than one best common ancestor for two commits. For example, with this
       topology:

	   ---1---o---A
	        /
		X
	       / 
	   ---2---o---o---B

       both 1 and 2 are merge-bases of A and B. Neither one is better than the other (both are best merge bases). When the --all option is not
       given, it is unspecified which best one is output.

       A common idiom to check "fast-forward-ness" between two commits A and B is (or at least used to be) to compute the merge base between A and
       B, and check if it is the same as A, in which case, A is an ancestor of B. You will see this idiom used often in older scripts.

	   A=$(git rev-parse --verify A)
	   if test "$A" = "$(git merge-base A B)"
	   then
		   ... A is an ancestor of B ...
	   fi

       In modern git, you can say this in a more direct way:

	   if git merge-base --is-ancestor A B
	   then
		   ... A is an ancestor of B ...
	   fi

       instead.

SEE ALSO

       git-rev-list(1), git-show-branch(1), git-merge(1)

GIT

       Part of the git(1) suite

Git 1.8.5.3							    01/14/2014							 GIT-MERGE-BASE(1)