Man google gave me 731,000 hits with "bash scripting examples"
Since I know that you are adept at using google, I would suggest
the ibm link bash by example, the linuxconfiwiki link
Also go back to that other thread on books, and have a look for bash scripting books offered by pureh@te ( I believe).
Also as far as security programs go just go to the program and open it up with your favorite editor and have a look at. You could even take one of the simpler ones make a copy of it and set it to run from a different directory and then play with the code.
netdiscover is a really simple program in this dept.
As for forums there are some that are more noob tolerable but they may not give answers to "hacking/pentest" type questions. Or info on the tools.
One such is http://www.linuxquestions.org/
www.unix.com is another.