Ldiff: Marking the differences between two LaTeX files

The Ldiff (LaTeX diff) script takes two LaTeX (or LyX) files as input
and generate a Postscript file that contains the changes between the
two files: Text that appears in both files is shown in black, text
that appears only in the first file is shown in red and is crossed
out, and text that appears only in the second file is shown in blue.
Note that in some cases, Ldiff will not give correct results.

Ldiff requires python >= 2.0 and dvipost (http://efeu.cybertec.at/).

WARNING: Ldiff might have unwanted effect on the current direcory. It
might be wise to backup your files before running it.