directory commands : cd
file commands (read, write, copy, move, delete ) : cat, touch, cp , mv, rm
OS commands for checking cpu/memory/disk usage : prstat, df
commands to zip files : zip, gzip
You can also check this URL to learn a little more about basic UNIX commands : A Basic UNIX Tutorial
I think it is time you began to create a library of a few books for your self-education.
I suggest you begin with this one from O'Reilly Press:
O'Reilly Press has a wealth of resources for you to examine.
You can buy the book direct from the publisher and from many other book sellers.