Package managers are tools to automate the process of installing, upgrading, uninstalling or configuring software on Linux. Package managers are part of the operating system and they use a single database for installation and a single packet format, for example: rpm or deb. They are also responsible for checking the digital signature, and dependency resolution for updates.

In a previous article, we showed the use of some useful commands for manipulating files and directories, in this case, several commands are presented which allow us to collect certain system information. Also, we will see that displaying the content of certain files, can also be a way for giving useful information. Furthermore, the use of session managing commands will be described.

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.