Linux Command Line guide

Do you think of the command line as an antiquated leftover from the past, or an old fashioned way of interacting with a computer? Think again. In Linux, it is the most flexible and powerful way to perform tasks. For example, searching for all .tmp files in a directory (and its sub-directories) and then deleting them can be a multi step process when done via graphical user interface, but is a matter of few seconds when done through the command line.