Book Image

Essential Linux Commands

By : Paul Olushile
Book Image

Essential Linux Commands

By: Paul Olushile

Overview of this book

The role of a system administrator is ever-evolving, with the Linux command line at its core. This makes Linux command-line mastery an essential skill to demonstrate your ability to efficiently manage and maintain systems efficiently. Essential Linux Commands addresses a diverse range of topics, including package management, file manipulation, networking strategies, system monitoring, and diagnostic tools. Each command is intricately explained to eliminate any ambiguity, ensuring ease of implementation in real-world scenarios. This book explains how to use SELinux to maintain security, run Linux machines on AWS Cloud, and transfer and download files to remote systems. With the help of practical examples and use cases, you’ll not only gain a thorough understanding of a command’s syntax but also grasp its functional breadth and limitations. The book also explores commands frequently used by system administrators to check network card statistics and firewall rules. Whether you’re a beginner or an experienced administrator, this book is an invaluable resource, filling in the gaps in your skill set and helping you improve your skills and expertise in Linux administration.
Table of Contents (20 chapters)
1
Part 1:Server Installations and Management Commands
5
Part 2:Frequently Used Commands – Part 1
9
Part 3:Frequently Used Commands – Part 2
15
Part 4:Linux Security and the Cloud

groupdel, groupmod, groupadd, and grpck

Group management is an important aspect of Linux system administration. Groups are used to organize users and define their access privileges to files and directories on the system. The four main commands used for group management are groupadd, groupmod, grpck, and groupdel.

groupadd is used to create a new group on the system. To use this command, type groupadd followed by the desired options and the new group name. For example, to create a new group called DevSec-group, the command would be groupadd DevSec-group:

Figure 2.18 – Adding a new group

Figure 2.18 – Adding a new group

This command will create a new group with the default settings, including a new GID.

Now that we’ve created our groups, let’s do some modifications such as changing its membership using the groupmod command. This is a command used to modify an existing group on the system. This command can be used to change the group’s name, GID, or membership...