Bourne shell scripting resources

[Doug Poland]

Hello,

Can someone point me to a good on-line reference for Bourne shell
scripting?  I've come across some syntax I don't understand and, since
I don't understand it, don't know how to search the web for it.

For example, what do these special variable characters do?

${UNISON_SCHED%% *}      #  what does %% * do?
${UNISON_JOB%\.*}        #  what does %\.* do?


-- 
Regards,
Doug