p4d2p is a Perl script which performs in-place editing on the output of
a previous 'p4 describe' command, to generate output suitable for patch(1).

p4genpatch is a Perl script which wraps 'p4 describe' to generate such
patches directly from the depot, when provided with a Perforce changelist
number.

Both utilities were written for development on Perl itself by Andreas Konig
and Gurusamy Sarathy, and were modified for use with multiple Perforce
depots by Simon Cozens.