On a centralized version control system, merge changes from
another branch into the current VC fileset. While developing a
branch, you may sometimes need to merge in changes that have
already been made in another branch. This is not a trivial
operation, as overlapping changes may have been made to the two
branches. On a decentralized version control system, merging is
done with the command C-x v m ( vc-merge). On Bazaar, this
prompts for the exact arguments to pass to bzr merge, offering a
sensible default if possible. On Git, this prompts for the name
of a branch to merge from, with completion (based on the branch
names known to the current repository). The output from running
the merge command is shown in a separate buffer. On a
centralized version control system like CVS, C-x v m prompts for
a branch ID, or a pair of revision IDs (see Switching Branches);
then it finds the changes from that branch, or the changes
between the two revisions you specified, and merges those
changes into the current VC fileset.