Cannot find FileMerge (opendiff tool) but I have xcode 4.6 installed

Question

When I attempt to run FileMerge as a GUI for Opendiff, I receive an error:

$ git mergetool -t opendiff
Merging:
Gemfile
Gemfile.lock
...

Normal merge conflict for 'Gemfile':
  {local}: modified file
  {remote}: modified file
Hit return to start merge resolution tool (opendiff): 
2013-12-26 20:00:20.248 opendiff[22367:e07] Couldn't find FileMerge
Gemfile seems unchanged.
Was the merge successful? [y/n] ^C
$

I have installed XCode 4.6.3 and Command Line Tools for Xcode April 2013. I am running OSX 10.7.5

I have tried solutions from the following two links with no success:

git diff with opendiff gives "Couldn't launch FileMerge" error

Is filemerge still available after Xcode 4.3 installation?

When I go to Xcode -> Open Developer Tool I do not see FileMerge in the list of options. There is a More Developer Tools link that takes me here: https://developer.apple.com/downloads/index.action?name=for%20Xcode%20-

How do I get FileMerge working?

Answer 1

FileMerge is located at within Xcode.

From the command-line:

cd /Applications/Xcode.app/Contents/Applications/
open .

Go into that directory once it opens:

1. Right-click on the app
2. Choose "Make alias"
3. Move that alias to your Applications directory

You're all set.