I am using the github advice to make it work: https://gist.github.com/329690
and right now my global config file contains:
[merge]
        tool = opendiff
        external = /Users/mike/bin/git-diff-cmd.sh
[diff]
        tool = opendiff
        external = /Users/mike/bin/git-diff-cmd.sh
However, when I use gif diff, the output still comes out as text output, and so is any merge conflict when using git merge <branch>.  Is there a sure way to make them use opendiff?  (when using git diff and git merge and preferably not by other commands)
 
    