CCL: Most Widely Used UNIX commands

Hi Folks,
I'm new to UNIX and to use cluster computing. I need help from you regarding the most widely used UNIX command for beowulf clusters. I have seen the webpages and learnt the basic commands. But i'm not sure about the commands that the computatinal chemist used ( to check the q system and so on)  I will be helpful if i was poited to some useful web addresess, or given some useful files.
Thanks in advance.