Introduction xxx Part I Performing Basic System Management Tasks Chapter 1 Installing Red Hat Enterprise Linux 3 "Do I Know This Already?" Quiz 3 Foundation Topics 6 Preparing to Install Red Hat Enterprise Linux 6 What Is Red Hat Enterprise Linux 9 Server? 6 Getting the Software 7 Using Red Hat Enterprise Linux 7 Using CentOS Stream 7 Other Distributions 8 Understanding Access to Repositories 8 Setup Requirements 9 Cert Guide Environment Description 9 Performing an Installation 10 Summary 22 Exam Preparation Tasks 23 End-of-Chapter Lab 24 Chapter 2 Using Essential Tools 27 "Do I Know This Already?" Quiz 27 Foundation Topics 30 Basic Shell Skills 30 Understanding Commands 30 Executing Commands 30 I/O Redirection 32 Using Pipes 34 History 35 Bash Completion 37 Editing Files with vim 37 Understanding the Shell Environment 40 Understanding Variables 40 Recognizing Environment Configuration Files 41 Using /etc/motd and /etc/issue 42 Finding Help 43 Using --help 43 Using man 43 Finding the Right man Page 44 Updating mandb 46 Using info 47 Using /usr/share/doc Documentation Files 48 Summary 49 Exam Preparation Tasks 49 End-of-Chapter Lab 51 Chapter 3 Essential File Management Tools 53 "Do I Know This Already?" Quiz 53 Foundation Topics 56 Working with the File System Hierarchy 56 Defining the File System Hierarchy 56 Understanding Mounts 57 Managing Files 61 Working with Wildcards 61 Managing and Working with Directories 61 Working with Absolute and Relative Pathnames 62 Listing Files and Directories 64 Copying Files and Directories 64 Moving Files and Directories 65 Deleting Files and Directories 66 Using Links 68 Understanding Hard Links 68 Understanding Symbolic Links 69 Creating Links 69 Removing Links 70 Working with Archives and Compressed Files 71 Managing Archives with tar 72 Creating Archives with tar 72 Monitoring and Extracting tar Files 73 Using Compression 74 Summary 75 Exam Preparation Tasks 76 End-of-Chapter Lab 77 Chapter 4 Working with Text Files 81 "Do I Know This Already?" Quiz 81 Foundation Topics 84 Using Common Text File-Related Tools 84 Doing More with less 84 Showing File Contents with cat 85 Displaying the First or Last Lines of a File with head and tail 86 Filtering Specific Columns with cut 87 Sorting File Contents and Output with sort 87 Counting Lines, Words, and Characters with wc 88 A Primer to Using Regular Expressions 89 Using Line Anchors 90 Using Escaping in Regular Expressions 91 Using Wildcards and Multipliers 91 Using Extended Regular Expressions 91 Using grep to Analyze Text 93 Working with Other Useful Text Processing Utilities 94 Summary 96 Exam Preparation Tasks 96 End-of-Chapter Lab 98 Chapter 5 Connecting to Red Hat Enterprise Linux 9 101 "Do I Know This Already?" Quiz 101 Foundation Topics 104 Working on Local Consoles 104 Logging In to a Local Console 104 Switching Between Terminals in a Graphical Environment 105 Working with Multiple Terminals in a Nongraphical Environment 107 Understanding Pseudo Terminal Devices 108 Booting, Rebooting, and Shutting Down Systems 109 Using SSH and Related Utilities 110 Accessing Remote Systems Using SSH 110 Using Graphical Applications in an SSH Environment 113 Securely Transferring Files Between Systems 114 Using scp to Securely Copy Files 114 Using sftp to Securely Transfer Files 115 Using rsync to Synchronize Files 115 Configuring Key-Based Authentication for SSH 116 Using Passphrases or Not? 116 Summary 117 Exam Preparation Tasks 118 End-of-Chapter Labs 119 Chapter 6 User and Group Management 121 "Do I Know This Already?" Quiz 121 Foundation Topics 124 Understanding Different User Types 124 Users on Linux 124 Working as Root 124 Using su 125 sudo 126 PolicyKit 127 Creating and Managing User Accounts 129 System Accounts and Normal Accounts 129 Creating Users 132 Modifying the Configuration Files 132 Using useradd 133 Home Directories 133 Default Shell 133 Managing User Properties 134 Configuration Files for User Management Defaults 134 Managing Password Properties 135 Creating a User Environment 135 Creating and Managing Group Accounts 137 Understanding Linux Groups 137 Creating Groups 137 Creating Groups with vigr 137 Using groupadd to Create Groups 138 Managing Group Properties 138 Summary 139 Exam Preparation Tasks 140 End-of-Chapter Labs 141 Chapter 7 Permissions Management 145 "Do I Know This Already?" Quiz 145 Foundation Topics 148 Managing File Ownership 148 Displaying Ownership 148 Changing User Ownership 149 Changing Group Ownership 150 Understanding Default Ownership 150 Managing Basic Permissions 151 Understanding Read, Write, and Execute Permissions 152 Applying Read, Write, and Execute Permissions 153 Managing Advanced Permissions 155 Understanding Advanced Permissions 155 Applying Advanced Permissions 157 Setting Default Permissions with umask 159 Working with User-Extended Attributes 160 Summary 162 Exam Preparation Tasks 162 End-of-Chapter Lab 164 Chapter 8 Configuring Networking 167 "Do I Know This Already?" Quiz 167 Foundation Topics 170 Networking Fundamentals 170 IP Addresses 170 IPv6 Addresses 171 IPv4 Network Masks 171 Binary Notation 172 MAC Addresses 173 Protocol and Ports 173 Managing Network Addresses and Interfaces 174 Validating Network Configuration 175 Validating Network Address Configuration 175 Validating Routing 178 Validating the Availability of Ports and Services 179 Managing Network Configuration with nmtui and nmcli 180 Required Permissions to Change Network Configuration 181 Configuring the Network with nmcli 182 Configuring the Network with nmtui 184 Working on Network Configuration Files 186 Setting Up Hostname and Name Resolution 187 Hostnames 187 DNS Name Resolution 189 Summary 191 Exam Preparation Tasks 191 End-of-Chapter Lab 193 Part II Operating Running Systems Chapter 9 Managing Software 195 "Do I Know This Already?" Quiz 195 Foundation Topics 198 Managing Software Packages with dnf 198 Understanding the Role of Repositories 198 Registering Red Hat Enterprise Linux for Support 199 Managing Subscriptions 200 Specifying Which Repository to Use 200 Understanding Repository Security 203 Creating Your Own Repository 204 Using dnf 206 Using dnf to Find Software Packages 206 Getting More Information About Packages 208 Installing and Removing Software Packages 209 Showing Lists of Packages 211 Updating Packages 213 Working with dnf Package Groups 214 Using dnf History 216 Managing Package Modules 217 Understanding dnf Modules 218 Managing Modules 218 Managing Software Packages with rpm 221 Understanding RPM Filenames 222 Querying the RPM Database 222 Querying RPM Package Files 223 Using repoquery 224 Summary 226 Exam Preparation Tasks 226 End-of-Chapter Labs 227 Chapter 10 Managing Processes 231 "Do I Know This Already?" Quiz 231 Foundation Topics 234 Introduction to Process Management 234 Managing Shell Jobs 234 Running Jobs in the Foreground and Background 234 Managing Shell Jobs 235 Understanding Parent-Child Relations 237 Using Common Command-Line Tools for Process Management 237 Understanding Processes and Threads 238 Using ps to Get Process Information 239 Understanding Process Priorities 241 Exploring Relations Between Slices 241 Managing Process Priorities 242 Sending Signals to Processes with kill, killall, and pkill 243 Killing Zombies 245 Using top to Manage Processes 246 Using tuned to Optimize Performance 248 Summary 250 Exam Preparation Tasks 250 End-of-Chapter Lab 251 Chapter 11 Working with Systemd 253 "Do I Know This Already?" Quiz 253 Foundation Topics 256 Understanding Systemd 256 Understanding Systemd Unit Locations 256 Understanding Systemd Service Units 257 Understanding Systemd Mount Units 258 Understanding Systemd Socket Units 259 Understanding Systemd Target Units 260 Managing Units Through Systemd 261 Managing Dependencies 263 Managing Unit Options 265 Summary 267 Exam Preparation Tasks 267 End-of-Chapter Lab 268 Chapter 12 Scheduling Tasks 271 "Do I Know This Already?" Quiz 271 Foundation Topics 274 Understanding Task Scheduling Options in RHEL 274 Using Systemd Timers 274 Configuring cron to Automate Recurring Tasks 276 Managing the crond Service 276 Understanding cron Timing 278 Managing cron Configuration Files 278 Understanding the Purpose of anacron 281 Managing cron Security 282 Configuring at to Schedule Future Tasks 282 Summary 283 Exam Preparation Tasks 284 End-of-Chapter Lab 285 Chapter 13 C.