Linux Basics for SysAdmin: Learn core linux concepts and command-line skills to kickstart your system administration career

Linux Basics for SysAdmin

Learn core linux concepts and command-line skills to kickstart your system administration career

Ryan Juan

Preface

For students, aspiring IT specialists, and working professionals, Linux Basics for SysAdmin is a great starting point for learning the fundamentals of Linux, including the command line and all the tools and commands needed to manage enterprise systems.

At first, you are introduced to the Linux environment, with a focus on browsing the filesystem, using basic commands, managing files and directories, and becoming acquainted with the shell. You'll also learn about package management and how to handle system startup and shutdown efficiently.

After that, you'll learn all about system configuration files, 'systemd' for managing system services, crontab for job scheduling, and 'at' and 'batch' for automating processes. You will also learn about system performance monitoring, log files, backup and restore procedures, disk partitioning, and remote management via SSH.

Afterwards, the book delves into topics such as dependency management, system hardware configuration, kernel upgrades, and device driver management, as well as package management with 'apt' and 'yum'. You'll also learn how to create and manage repositories, and install and setup virtual machines with VirtualBox. In the end, the book covers a wide range of topics, including creating and managing user accounts, editing user profiles, setting ownership and permissions for files, using ACLs, managing user sessions, configuring sudo for administrative tasks, implementing password policies, working with PAM, and managing group memberships.

In this book you will learn how to:

Master essential Linux commands to efficiently navigate and manage the system's file structure.

Gain proficiency in user and group management to ensure secure access control and permissions.

Learn to configure and manage system services with systemd for streamlined service administration.

Implement and enforce robust password policies for enhanced security and user account protection.

Understand and utilize package management tools for seamless software installation.

Set up and manage virtual machines with VirtualBox to create isolated, reproducible development environments.

Use Access Control Lists (ACLs) to fine-tune file permissions beyond the standard Unix model.

Schedule and automate tasks using cron, at, and batch to improve system efficiency and reliability.

Monitor system performance and logs to proactively identify and address potential issues.

Securely configure and use SSH for remote management and administration of Linux systems.

An understanding of the basics of Linux system administration will be yours by the time you finish this book.

Also, there is a companion book called Linux Advanced for SysAdmin for anyone who want to learn more advanced Linux techniques, by the same Author ‘Ryan Juan’. Concepts like advanced database management, security configuration, network management, system monitoring, and advanced operations including deployments, load balancing, and working with Kubernetes are the main focus of this follow-up book. Each of these books, taken together, provide a solid foundation and advanced expertise for both aspiring and practicing Linux system administrators.

Prologue

You have arrived at Linux Basics for SysAdmin, a book that will teach you the ropes of Linux so that you may confidently administer Linux systems. Whether you're an experienced IT professional looking to hone your skills, a student eager to learn Linux, or someone in between, this book will cover all you need to know to become a competent system administrator.

A large number of computers, desktops, and mobile devices throughout the globe run Linux because of its flexibility and power. It is a priceless asset to the IT sector due to its open-source nature, robustness, and adaptability. Understanding the fundamental concepts that make Linux systems secure, efficient, and dependable is more important than simply knowing commands and configurations if you want to become an expert Linux user.

Beginning with the fundamentals, this book will provide you with the groundwork you need to become proficient with Linux. Up and Running with Linux Systems, the first chapter, provides an overview of the Linux environment. A fundamental understanding of the shell, file and directory management, and command syntax will be covered. We also go over the basics of system starting and shutdown, managing packages, and the utilities that are needed for Linux administration.

Next, in Chapter 2, Managing Linux Systems, we will explore system management in more detail. Discover the ins and outs of configuration files, learn how to use systemd to control services, crontab to schedule activities, and monitor system performance. Partitioning disks, managing log files, and SSH-based remote administration are all covered in this chapter.

When it comes to managing software and hardware, Chapter 3 is where it's at. This chapter will teach you the ins and outs of using apt and yum for package management, dealing with dependencies, configuring your system's hardware, and upgrading the kernel. Docker and VirtualBox, two popular tools for creating and managing virtual machines, are also covered in this chapter.

Chapter 4, User and Permission Management, discusses how to manage users and permissions. Access Control Lists (ACLs), file ownership and permission settings, user profile editing, and account creation and management are all part of what you can expect. You will also be responsible for managing group memberships, working with Pluggable Authentication Modules (PAM), implementing password restrictions, configuring sudo, and user sessions.

This book will provide you the core concepts of Linux system administration practically, so you can start managing your systems with confidence. Starting here will go you far in the IT career path you desire by making you an expert Linux system administrator.

Copyright © 2024 by GitforGits

All rights reserved. This book is protected under copyright laws and no part of it may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without the prior written permission of the publisher. Any unauthorized reproduction, distribution, or transmission of this work may result in civil and criminal penalties and will be dealt with in the respective jurisdiction at anywhere in India, in accordance with the applicable copyright laws.

Published by: GitforGits

Publisher: Sonal Dhandre

www.gitforgits.com

[email protected]

Printed in India

First Printing: May 2024

Cover Design by: Kitten Publishing

For permission to use material from this book, please contact GitforGits at [email protected].

Content

Preface

GitforGits

Acknowledgement

Chapter I: Up and Running with Linux Systems

Overview

Understanding Linux Ubuntu

Navigating the Linux Filesystem

Basic Linux Commands

Network Configuration and Troubleshooting

‘ip’ and ‘ifconfig’

‘mtr’

File and Text Processing

‘find’

‘awk’

Network Monitoring and Diagnostics

‘tcpdump’

‘netstat’

‘nslookup’

System and Process Management

‘sudo’

‘tmux’

‘lsns’

‘pkill’

Email and Web Requests

‘mail’

‘curl’

‘watch’

Sample Program: Putting All Commands Together

Network Configuration and Diagnostics

Searching and Processing Files

Capturing and Analyzing Network Traffic

DNS Queries and Network Statistics

System and Process Management

Email and Web Requests

Monitoring System Changes

File and Directory Management

Setting up the Directory Structure

Creating Files and Directories

Accessing Hidden Files and Directories

Viewing File and Directory Permissions

Changing File and Directory Permissions

Setting Ownership

Accessing Secured Files

Understanding Permissions and Access Control

Managing Large Files and Directories

Moving and Copying Files

Deleting Files and Directories

Finding Files Based on Permissions

Working with Links

Archiving and Compressing Files

File Integrity and Security

Scheduling Regular Tasks

Monitoring File and Directory Changes

Introduction to Shell

Purpose of Shell

Introducing Bash

Basic Bash Commands

Navigating Directories

Listing Directory Contents

Creating and Deleting Files

Copying and Moving Files

Using Command History

Tab Completion

Bash Variables

Bash Scripting

Conditional Statements

Loops in Bash

Functions in Bash

Basics of Package Management

Purpose of Managing Packages

Updating Package Lists and Upgrading Software

Installing Packages

Viewing Installed Packages

Deleting Packages

Finding Packages

Working with Repositories

Pinning Packages

Sample Program: Managing Packages for AlphaProject

System Startup and Shutdown

Shutting Down and Rebooting the System

Booting the System

Automating Startup and Shutdown

Managing Specific Services

Starting and Stopping Services

Enabling and Disabling Services at Boot

Checking Service Status

Sample Program: Managing AlphaProject Services

Scheduling Service Management with Cron

Logging and Monitoring Services

Managing Processes

Stages of a Process

Displaying Running Processes

Starting and Terminating Processes

Adjusting Process Priority

Suspending and Resuming Processes

Monitoring Process Activity

Sample Program: Managing Processes for AlphaProject

Starting a Web Server

Running a Background Script

Monitoring Web Server Activity

Terminating a Misbehaving Process

Changing the Priority of a Backup Process

Suspending and Resuming Long-Running Compilation

Automating Process Management with Cron

Monitoring Processes with ‘ps’ and ‘top’

Tracing a Problematic Process

Using ‘lsof’ to Check Open Files

Sample Workflow: Handling High CPU Usage

Identify the High CPU Process

Adjust the Priority

Monitor the Process

Terminate If Necessary

Accessing and using Linux Utilities

Role of Utilities

Common Utilities for AlphaProject

File and Directory Management Utilities

‘cp’, ‘mv’, and ‘rm’

‘find’

Text Processing Utilities

‘grep’

‘sed’

‘awk’

Network Utilities

‘ping’

‘traceroute’

‘netstat’

‘curl’

System Monitoring Utilities

‘top’ and ‘htop’

‘df’ and ‘du’

Archiving and Compression Utilities

‘tar’, ‘gzip’, and ‘zip’

Disk Usage and Partition Management Utilities

‘fdisk’ and ‘lsblk’

Sample Program: Using Utilities in AlphaProject

File Backup and Management

Log Analysis

Configuration Management

Network Diagnostics

System Monitoring

Disk Space Management

Archiving Project Data

Downloading Resources

Disk Partition Analysis

Summary

Chapter II: Managing Linux Systems

Overview

Getting around System Configuration Files

Characteristics of System Configuration Files

Categories of Configuration Files

Customizing Configuration Files

Editing Configuration Files

Backup Configuration Files

Understanding Configuration Syntax

Sample Program: Customizing Configuration Files

Customizing Network Settings

Configuring SSH

Setting up User Accounts

Configuring Apache Web Server

Managing Services

Configuring User and Group Permissions

Setting System Locale

Automating Configuration Changes

Managing System Services with ‘systemd’

‘systemd’ Components

Managing System Services with systemd

Viewing Service Status

Starting and Stopping Services

Restarting and Reloading Services

Enabling and Disabling Services at Boot

Checking All Services

Analyzing Boot Performance

Managing Dependencies

Creating Custom Service Units

Logging with journalctl

Handling Service Failures

Sample Program: Using ‘systemd’ to Manage AlphaProject Services

Using ‘crontab’

Introduction to Cron Utility

Understanding crontab

Sample Program: Using crontab in AlphaProject

Setting up a Backup Job

Cleaning up Temporary Files

Monitoring System Health

Sending Email Notifications

Rotating Logs

Custom Scheduling with Step Values

Viewing and Managing Cron Jobs

Scheduling Tasks with ‘at’ and ‘batch’

Introduction to ‘at’ and ‘batch’

Using at and batch in AlphaProject

Scheduling One-Time Tasks with at

Scheduling Tasks with Relative Time

Scheduling Tasks with Specific Dates

Using batch for System Load-Dependent Tasks

Combining at and batch with Other Utilities

Automating System Health Checks

Managing and Viewing Logs

Monitoring System Performance

Key Metrics to Monitor

System Performance Monitoring Tools

‘top’

‘vnstat’

‘nagios’

‘iftop’

‘psacct’

‘iostat’

‘netstat’

Sample Program: Monitoring Tools in AlphaProject

Monitoring CPU and Memory Usage

Tracking Network Traffic

Comprehensive System Monitoring with Nagios

Real-Time Network Monitoring with iftop

Detailed Process Accounting with psacct

Disk and I/O Statistics with iostat

Network Connections and Statistics with netstat

Log Files and System Logging

What Can Be Logged in Linux

Understanding Syslogs

Managing Syslogs with rsyslog

Installing and Configuring rsyslog

Understanding the rsyslog Configuration

Basic Configuration Example

Customizing System Logs for AlphaProject

Accessing and Analyzing Logs

Setting up Log Rotation

Remote Logging

Monitoring Logs with Logwatch

Sample Program: Logging Messages

Custom Application Logging

Log Rotation for Application Logs

Remote Logging Setup

Backing up and Restoring Systems

‘rsync’

Key Features of rsync

Using rsync for AlphaProject

Installing rsync

Backing up Data with rsync