the default shell for Linux dist. is bash. (Bourne Again shell)
other shells including csh and tcsh
mac os x use tcsh as default
All shell usually share the same standard unix utility .
example: cd (change dir), ls (list or sth ) etc.
but they differ usually when you try to set path .
if you're not sure about setting path, you can consult some tutorial/manuals
path can search your env variable. to make it permanent, you have to edit your .tcsh file or .csh
use ls -a
to see all files including the dots in the beginning.
hope that help