This is the Debian GNU/Linux prepackaged version of the es shell.
es was written by Paul Haahr and Byron Rakitzis.

This package was put together by Ian Murdock <imurdock@debian.org>,
from sources obtained from:
 ftp.white.toronto.edu:/pub/es/es-0.84.tar.Z

Changes:
 * added Debian GNU/Linux package maintenance system files
 * added necessary `#ifdef's and `#ifndef's for compilation
   under Linux

es is in the public domain.
