x10ephem computes sunrise and sunset times. It consists of a library and an assortment of utilities. The most useful utility is x10events, which parses crontab files and updates the time fields to track sun events. Combined with an X10 interface like HEYU or X10, this allows the scheduling of lighting events to follow the changing seasons and daylight savings time automatically. This application does not depend on X10; it can be used for any crontab entry you like.
xtctl is a script for setting/changing xterm properties. It can change the foreground, background, cursor, and mouse colours of an XTerm window, and the icon and background image (only known to work with Eterm). xtctl can also modify the window's title, icon name, highlight background, font, size, position, z-order (raise and lower), and iconified/restored status. There are experimental options for full and soft reset.
Zsh is a UNIX command interpreter (shell) which of the standard shells most resembles the Korn shell (ksh). It includes enhancements of many types, notably in the command-line editor, options for customising its behaviour, filename globbing, features to make C-shell (csh) users feel more at home and extra features drawn from tcsh.