Although Linux had progressed far from being a command-line only OS to a full fledged totally GUI based one, sometimes, the command line is the best way to get something done. Here are 5 of the must-know commands. These commands can b quite useful and handy. 1: mount: Used for mounting Windows/Other partitions, just in case it isn’t automatically mounted. Usage: mount here refers to the special device where your partitions are.