opendiff ( FileMerge ) stopped working with git on Mac OS X

Question

I was using opendiff with git as the difftool on Mac OS X and today it just stopped working.
It does not give an error message, it just defaults to dumping the diff on the terminal.

I've followed the common guides on how to configure this, but to no avail:

• Created an executable script with:

  #!/bin/sh  
  /usr/bin/opendiff "$2" "$5" -merge "$1"
  

• Added options to .gitconfig:

  external = ~/git-diff-cmd.sh
  tool = opendiff
  

But it doesn't work.
Actually, FileMerge was automatically recognized and launched before without even using this script and configuration, just doing git difftool -t opendiff {filename} would do.

Answer 1

Try setting environment variable

export GIT_EXTERNAL_DIFF=<path to your script>