That depends on the editer you wish to use.
For most config files, you need to be root, so su to root and try:
pico /etc/fstab
Pico is a fairly simple editor form the command line.
You couls also try this:
mc
mc is Midnight Commander and this is a nice quick browser with editing capability.
Or, how about this:
jed /etc/fstab
Thats kinda cool.
vi and emacs too... no comment
HTH
