What is sed? Sed is a stream editor which is used to perform basic text transformations on an input stream (a file or input from a pipeline) or filter strings. It permits to modify the contents of different lines in a file, based on some parameters. For the examples shown in this article, you used the 4.2.1 version of sed as shown below: sed --version GNU sed version 4.2.1 Copyright (C) 2009 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE,…

Results presentation The way in which the research results are presented has a significant impact on readers. Also, a good way to represent the information gives a clear and easy ideas to understand. For this, we need a selection of tools that allow the reproduction of documents, photographs, graphics, and other associated items. On the other hand, there are various applications which facilitate the data processing when we need to work with research result, whether mathematical or network.

Linux is a multiuser and multitasking operating system, ie, multiple users can work on the system simultaneously running several tasks at once. It is therefore, very important that the operating system allows the management and control of users. Unix based systems organize all this by users and groups, where each user must be identified with a user name and password. During login, the password entered by each user, is encrypted and compared to the encrypted passwords that were previously stored in the system.

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.