Before starting with the use of some Linux commands, I want to remind the importance of reviewing the reference manual for each command, because this is the place where you can find all the possible options. The reference manual can be displayed on a terminal using the "man" command, for example, if we see the manual of the "man" command in a terminal, we should write "man man" and we would see something like this: Figure # 1: Linux terminal displaying the manual of the man command.