Shell Scripting Resources
A brief tutorial on "sh" shell scripting. Nice short overall summary.
A longer tutorial on "sh" scripting. More detail.
Beware his description of "rsh" commands... for security reasons, those should be avoided in favor of "ssh" equivalents.
"Linux Shell Scripting Tutorial"
A very detailed tutorial geared towards Linux.
Quotes in the shell :
Deals with those tricky issues of backslashes, quotation marks, etc.