Zsh1 is a shell designed for interactive use, although it is also a powerful scripting language. Many of the useful features of bash, ksh, and tcsh were incorporated into zsh; many original features were added. The introductory document details some of the unique features of zsh. It assumes basic knowledge of the standard UNIX shells; the intent is to show a reader already familiar with one of the other major shells what makes zsh more useful or more powerful.