(zsh) 1. sh with list processing and database enhancements.
Version 2.1.o (before 1995-10-30).
2. A unix command interpreter shell by Paul Falstad <email@example.com> some time before 1993-03-23. It is similar to, but not completely compatible with, ksh, with many additions to please csh users and some tcsh features. zsh supports editing of multi-line commands in a single buffer; variable editing; a command buffer stack; recursive globbing; manipulation of arrays; and spelling correction.
zsh uses gnu autoconf so should compile and run on any modern version of UNIX, and many not-so-modern.
Current version: 4.0.6, as of 2002-10-02.