whohas is a command line tool that allows querying several package
lists at once. whohas is written in Perl and was designed to help
package maintainers find ebuilds, pkgbuilds and similar package
definitions from other distributions to learn from. However, it
can also be used by normal users who want to know:

- Which distribution has packages available for apps upon whom the
user depends.

- What version of a given package is in use in each distribution,
or in each release of a distribution (implemented only for Debian).

Homepage:
http://www.philippwesche.org/200811/whohas/intro.html
