using FileMerge as git difftool on Mac OS X

gdiff

#!/bin/bash
# my git difftool, calls FileMerge with project as -merge target
# better than using opendiff
#
# cd to your project dir and and run difftool like this:
#   git difftool -d -x gdiff

# find top level of git project
dir=$PWD
until [ -e "$dir/.git" ]; do
  if [ "$dir" == "/" ]; then
    echo "Not a git repository" >&2
    exit 1;
  fi
  dir=`dirname "$dir"`
done

# open fresh FileMerge and wait for termination, avoids issues with git temp files
open -a FileMerge -n -W --args -left "$1" -right "$2" -merge "$dir"

# references:
# http://hints.macworld.com/article.php?story=20070220223441729
# https://gist.github.com/bkeating/329690

I call this script "gdiff". Put it somewhere on your $PATH. Note, the -d option is required for this to work correctly. That means do a full directory comparison rather than individual files. Call it like this:

git difftool -d -x gdiff

Of course, you can put that in an alias or bash script to save typing. And there are other git config options you can tweak to make it your default.

By the way, FileMerge comes with the Xcode tools. Get Xcode from https://developer.apple.com/xcode/downloads/

Thank you for sharing this! I was struggling with how to get git directory diffs with FileMerge - this is the only solution I have seen that works reliably.

I've made a couple enhancements to this gist at https://gist.github.com/gwarnes-mdsol/b0aff96fbb7a4c92e570e7b03daa7e1b. To get a diff do:
git diff -r 9607ab015c6c39f9b77a8564126a23e74c890dcd

(Won't it be nice when github allows gist pull requests!)