git-merge-tree(1) mojave man page | unix.com

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

NAME
       git-merge-tree - Show three-way merge without touching index

SYNOPSIS
       git merge-tree <base-tree> <branch1> <branch2>

DESCRIPTION
       Reads three tree-ish, 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.

GIT
       Part of the git(1) suite

Git 2.17.1                                                          10/05/2018                                                   GIT-MERGE-TREE(1)