xd is a GUI wrapper for git/svn diff, it is not a diff tool itself.

Usage:

    xd [diff] [any arguments or options acceptable to git or svn]

  Everytime you want to run 'git diff' or 'svn diff', you can run 'xd diff'
  instead, xd would display a list of the files as well as a preview window,
  you can double click on the file to launch any external diff tool of your
  choice.

  On command line, 'diff' is optional, running 'xd diff' is equivalent to
  running 'xd'.

  For git, you can also run 'xd show' which is equivalent to 'git show'.

Requirement:

  The current directory must be managed by git or svn where xd is started.

Install:

  xd requires python >= 2.4 and tk >= 8.4, run 'python -m Tkinter' to verify
  if you have all required components installed.

  If not, you can do:

   sudo yum install tkinter # for rpm based systems

  Or:

   sudo apt-get install python-tk # for deb based systems

  You can install xd anywhere you see fit, somewhere in your PATH would be
  good.

Diff Tool:

  xd supports tkdiff, xxdiff, gvimdiff, emacs(ediff), xemacs(ediff), meld,
  diffuse, kompare and kdiff3. They need to be in your PATH.

  You can also start any custom diff tool you like.

How it works:

  xd uses the external diff mode for git/svn to get the files to diff.

Extending:

  xd is a simple python script so it is very easy to add support for other SCM
  systems and diff tools.