git-merge-tree - Show three-way merge without touching index
git merge-tree <base-tree> <branch1> <branch2>
Reads three treeish, and output trivial merge results and conflicting
stages to the standard output. This is similar to what three-way git
read-tree -m does, but instead of storing the results in the index, the
command outputs the entries to the standard output.
This is meant to be used by higher level scripts to compute merge
results outside of the index, and stuff the results back into the
index. For this reason, the output from the command omits entries that
match the <branch1> tree.
Written by Linus Torvalds <email@example.com>
Documentation by Junio C Hamano and the git-list
Part of the git(1) suite