In producing this document, I have borrowed heavily from the work of the Bashprompt project, which was at http://bash.current.nu/. This site was removed from its server as of July 2001 but Robert Current, the admin, assured me it would reappear soon. Unfortunately, it appears he's now (May 2003) let his domain registration lapse. The work of that project is carried on indirectly by Bashish (http://bashish.sourceforge.net/), with whom I've had no contact. Other sources used include the xterm Title mini-HOWTO by Ric Lister, available at http://www.tldp.org/HOWTO/mini/Xterm-Title.html, Ansi Prompts by Keebler, available at http://www.ncal.verio.com/~keebler/ansi.html (now deceased), How to make a Bash Prompt Theme by Stephen Webb, available at http://bash.current.nu/bash/HOWTO.html (also deceased), and X ANSI Fonts by Stumpy, available at http://home.earthlink.net/~us5zahns/enl/ansifont.html.
Also of immense help were several conversations and e-mails from Dan, who used to work at Georgia College & State University, whose knowledge of Unix far exceeded mine. He gave me several excellent suggestions, and ideas of his have led to some interesting prompts.
Three books that have been very useful while programming prompts are Linux in a Nutshell by Jessica Heckman Perry (O'Reilly, 3rd ed., 2000), Learning the Bash Shell by Cameron Newham and Bill Rosenblatt (O'Reilly, 2nd ed., 1998) and Unix Shell Programming by Lowell Jay Arthur (Wiley, 1986. This is the first edition, the fourth came out in 1997).