http://www.cryptonomicon.com/beginning.html The Neal Stephenson essay, "In the Beginning Was the Command Line." See also an authorized "update" by Garrett Birkel, "The Command Line in 2004," at http://home.earthlink.net/~android606/commandline.
http://www.gnu.org/software/bash The official bash site at the GNU Project. Download the latest, and read the Introduction to Bash.
http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html Chet Ramey's bash site. Ramey is the current bash maintainer. Looks very much like the official page, but also has the bash FAQ list.
http://www.tldp.org/LDP/Bash-Beginners-Guide/html A bash guide for beginners.
http://ldp.nllgg.nl/LDP/abs/html The Advanced bash scripting guide. "This tutorial assumes no previous knowledge of scripting or programming, but progresses rapidly toward an intermediate/advanced level of instruction." Read online, or download the PDF or the SGML source.
http://www.filibeto.org/sun/lib/development/shell/config_the_bash_shell.html Configuring the bash shell.
http://www.justlinux.com/nhf/Shells/Basic_Console_Commands.html Learn these commands and you can be comfortable saying you know bash "well enough."
http://www.kornshell.com/doc Assorted documentation for the commercial Korn shell, ksh.
http://web.cs.mun.ca/~michael/pdksh The public domain Korn shell site. This is the version included with SUSE Linux.
http://www.tcsh.org The tcsh wiki. Although it does not contain a wealth of information, check out the FAQ and TipsNTricks page. You can also subscribe to the two tcsh mailing lists.
http://www.faqs.org/faqs/unix-faq/shell/csh-whynot Perl guru Tom Christiansen's famous 1996 essay, "Csh Programming Considered Harmful." Why it's a bad idea to script in the C shell.
http://www.zsh.org Home of the Z shell. Very useful.
