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The best-selling, hands-on roadmap to acing the new Linux+ exam
In the newly updated Fifth Edition of CompTIA Linux+ Study Guide: Exam XK0-005, IT industry veterans and tech education gurus Richard Blum and Christine Bresnahan deliver a concise and practical blueprint to success on the CompTIA Linux+ exam and in your first role as a Linux network or system administrator.
In the book, you’ll find concrete strategies and proven techniques to master Linux system management, security, scripting, containers, automation, and troubleshooting. Every competency tested on the Linux+ exam is discussed here. You’ll also get:
Perfect for practicing network and system admins seeking an in-demand and valuable credential for working with Linux servers and computers, CompTIA Linux+ Study Guide: Exam XK0-005, Fifth Edition, will also earn a place in the libraries of people looking to change careers and start down an exciting new path in tech.
RICHARD BLUM has over 35 years of experience working as a system and network administrator. He teaches online courses in Linux and Web programming and is co-author with Christine Bresnahan of several Linux titles, including CompTIA Linux+ Study Guide, Linux Essentials, Mastering Linux System Administration, and the Linux Command Line and Shell Scripting Bible.
CHRISTINE BRESNAHAN has over 35 years of experience working in the IT industry. She is an Adjunct Professor at Ivy Tech Community College where she teaches Linux certification and Python programming classes. She is co-author with Richard Blum of CompTIA Linux+ Study Guide, Linux Essentials, Mastering Linux System Administration, and the Linux Command Line and Shell Scripting Bible.
Introduction xxxi
Assessment Test xliv
Answers to Assessment Test lv
Part I Gathering Your Tools 1
Chapter 1 Preparing Your Environment 3
Setting Up a Learning Space 4
Using That Old Laptop 4
Creating a Virtualized Environment 5
Jumping to the Cloud 7
Exploring Linux Distributions 8
Looking at Red Hat Enterprise Linux 9
Looking at Ubuntu 10
Looking at openSUSE 11
Looking at Fedora 12
Locating a Terminal 14
Summary 15
Chapter 2 Introduction to Services 17
What Is a Linux Server? 18
Launching Services 19
Listening for Clients 20
Serving the Basics 22
Web Servers 22
Database Servers 23
Mail Servers 25
Serving Local Networks 27
File Servers 27
Print Servers 28
Network Resource Servers 29
Implementing Security 31
Authentication Server 31
Certificate Authority 33
Access Server (SSH) 33
Virtual Private Networks 34
Proxy Server 34
Monitoring 34
Improving Performance 35
Clustering 35
Load Balancing 35
Containers 35
Summary 36
Exam Essentials 37
Review Questions 38
Chapter 3 Managing Files, Directories, and Text 43
Handling Files and Directories 44
Viewing and Creating Files 44
Copying and Moving Files 50
Removing Files 56
Linking Files and Directories 60
Establishing a Hard Link 60
Constructing a Soft Link 62
Reading Files 63
Reading Entire Text Files 64
Reading Text File Portions 66
Reading Text File Pages 70
Finding Information 71
Viewing File Information 72
Exploring File Differences 72
Using Simple Pinpoint Commands 75
Using Intricate Pinpoint Commands 79
Summary 82
Exam Essentials 83
Review Questions 84
Chapter 4 Searching and Analyzing Text 89
Processing Text Files 90
Filtering Text 90
Formatting Text 95
Determining Word Count 99
Redirecting Input and Output 101
Handling Standard Output 101
Redirecting Standard Error 102
Regulating Standard Input 104
Piping Commands 106
Creating Here Documents 108
Creating Command Lines 109
Editing Text Files 111
Appreciating Text Editors 111
Learning about Stream Editors 116
Summary 123
Exam Essentials 124
Review Questions 125
Part II Starting Up and Configuring Your System 131
Chapter 5 Explaining the Boot Process 133
The Linux Boot Process 134
Following the Boot Process 134
Viewing the Boot Process 135
The Firmware Startup 136
The BIOS Startup 136
The UEFI Startup 137
Linux Bootloaders 138
GRUB Legacy 139
GRUB2 143
Alternative Bootloaders 145
System Recovery 146
Kernel Failures 146
Root Drive Failure 148
Summary 150
Exam Essentials 150
Review Questions 152
Chapter 6 Maintaining System Startup and Services 157
Looking at init 158
Managing systemd Systems 159
Exploring Unit Files 160
Focusing on Service Unit Files 162
Focusing on Target Unit Files 167
Looking at systemctl 168
Examining Special systemd Commands 172
Managing SysV init Systems 178
Understanding Runlevels 178
Investigating SysV init Commands 182
Digging Deeper into systemd 187
Looking at systemd Mount Units 187
Exploring Automount Units 189
Focusing on Timer Unit Files 190
Summary 191
Exam Essentials 191
Review Questions 194
Chapter 7 Configuring Network Connections 199
Configuring Network Features 200
Network Configuration Files 201
Graphical Tools 203
Command-Line
Tools 205
Command-Line
Networking Tool 214
Basic Network Troubleshooting 217
Sending Test Packets 217
Finding Host Information 219
Advanced Network Troubleshooting 222
The netstat Command 222
Examining Sockets 226
Monitoring the Network 226
Summary 228
Exam Essentials 229
Review Questions 231
Chapter 8 Comparing GUIs 235
Focusing on the GUI 236
Getting to Know GNOME 237
Probing KDE Plasma 239
Considering Cinnamon 241
Making Acquaintance with MATE 243
Setting Up Accessibility 245
Serving Up the GUI 247
Figuring Out Wayland 248
Examining X11 250
Using Remote Desktops 252
Viewing VNC 252
Grasping Xrdp 254
Exploring NX 256
Studying SPICE 257
Forwarding 257
Local 259
Remote 260
Tunneling Your X11 Connection 261
Summary 262
Exam Essentials 262
Review Questions 264
Chapter 9 Adjusting Localization Options 269
Understanding Localization 270
Character Sets 270
Environment Variables 271
Setting Your Locale 272
Installation Locale Decisions 272
Changing Your Locale 272
Looking at Time 275
Working with Time Zones 275
Setting the Time and Date 276
Watching System Time 280
Summary 281
Exam Essentials 282
Review Questions 284
Part III Managing Your System 289
Chapter 10 Administering Users and Groups 291
Managing User Accounts 292
Adding Accounts 292
Maintaining Passwords 304
Modifying Accounts 306
Deleting Accounts 308
Managing Groups 309
Setting Up the Environment 313
Perusing Bash Parameters 313
Understanding User Entries 314
Grasping Global Entries 316
Querying Users 316
Exploring the whoami Utility 316
Understanding the who Utility 317
Identifying with the id Program 318
Displaying Access History with the last Utility 319
Managing Disk Space Usage 320
Summary 323
Exam Essentials 324
Review Questions 325
Chapter 11 Handling Storage 329
Storage Basics 330
Drive Connections 330
Partitioning Drives 331
Automatic Drive Detection 331
Partitioning Tools 332
Working with fdisk 332
Working with gdisk 334
The GNU parted Command 336
Graphical Tools 337
Understanding Filesystems 337
The Virtual Directory 338
Maneuvering around the Filesystem 341
Formatting Filesystems 341
Common Filesystem Types 341
Creating Filesystems 343
Mounting Filesystems 344
Manually Mounting Devices 344
Automatically Mounting Devices 345
Managing Filesystems 346
Retrieving Filesystem Stats 346
Filesystem Tools 348
Storage Alternatives 349
Multipath 350
Logical Volume Manager 350
Using RAID Technology 354
Encrypting Partitions 355
Summary 358
Exam Essentials 358
Review Questions 360
Chapter 12 Protecting Files 363
Understanding Backup Types 364
Looking at Compression Methods 366
Comparing Archive and Restore Utilities 368
Copying with cpio 369
Archiving with tar 372
Duplicating with dd 377
Replicating with rsync 380
Securing Offsite/Off-System
Backups 382
Copying Securely via scp 382
Transferring Securely via sftp 384
Checking Backup Integrity 387
Digesting an MD5 Algorithm 387
Securing Hash Algorithms 388
Summary 389
Exam Essentials 389
Review Questions 390
Chapter 13 Governing Software 393
Working with Source Code 394
Downloading Source Code 394
Bundling Source Code Packages 395
Compiling Source Code 399
Packaging Applications 400
Installing and Managing Packages 401
Understanding Repositories 405
Using Application Containers 413
Using Snap Containers 414
Using Flatpak Containers 416
Summary 418
Exam Essentials 419
Review Questions 421
Chapter 14 Tending Kernel Modules 423
Exploring Kernel Modules 424
Installing Kernel Modules 428
Removing Kernel Modules 431
Summary 432
Exam Essentials 432
Review Questions 434
Part IV Securing Your System 437
Chapter 15 Applying Ownership and Permissions 439
Looking at File and Directory Permissions 440
Understanding Ownership 440
Controlling Access Permissions 442
Exploring Special Permissions 445
Managing Default Permissions 446
Access Control Lists 448
Context-Based
Permissions 450
Using SELinux 451
Using AppArmor 455
Understanding Linux User Types 457
Types of User Accounts 458
Escalating Privileges 458
Restricting Users and Files 459
Summary 464
Exam Essentials 465
Review Questions 466
Chapter 16 Looking at Access and Authentication
Methods 469
Getting to Know PAM 470
Exploring PAM Configuration Files 471
Enforcing Strong Passwords 474
Locking Out Accounts 477
Limiting Root Access 481
Exploring PKI Concepts 483
Getting Certificates 483
Discovering Key Concepts 483
Securing Data 484
Signing Transmissions 485
Using SSH 486
Exploring Basic SSH Concepts 486
Configuring SSH 488
Generating SSH Keys 490
Authenticating with SSH Keys 492
Authenticating with the Authentication Agent 494
Using SSH Securely 496
Using VPN as a Client 498
Summary 499
Exam Essentials 499
Review Questions 501
Chapter 17 Implementing Logging Services 503
Understanding the Importance of Logging 504
The syslog Protocol 504
The History of Linux Logging 506
Basic Logging Using rsyslog 507
Configuration 507
Making Log Entries 509
Finding Event Messages 509
Journaling with systemd-journald 510
Configuration 510
Viewing Logs 511
Summary 513
Exam Essentials 514
Review Questions 515
Chapter 18 Overseeing Linux Firewalls 517
Providing Access Control 518
Looking at Firewall Technologies 520
Familiarizing Yourself with firewalld 521
Investigating iptables 525
Exploring nftables 530
Understanding UFW 533
Forwarding IP Packets 539
Dynamically Setting Rules 539
DenyHosts 539
Fail2Ban 540
IPset 540
Summary 542
Exam Essentials 542
Review Questions 544
Chapter 19 Embracing Best Security Practices 547
User Security 548
Authentication Methods 548
Multifactor Authentication 550
Unique User Accounts 551
Enforce Strong Passwords 551
Restricting the Root Account 553
Separation of Data 555
Disk Encryption 556
Restricting Applications 556
Preventing Unauthorized Rebooting 557
Restricting Unapproved Jobs 559
Banners and Messages 559
Restricting USB Devices 559
Looking for Trouble 560
Auditing 561
Network Security 561
Denying Hosts 561
Disabling Unused Services 562
Changing Default Ports 562
Using Encryption on the Network 563
Summary 564
Exam Essentials 565
Review Questions 567
Part V Troubleshooting Your System 571
Chapter 20 Analyzing System Properties and Remediation 573
Troubleshooting the Network 574
Exploring Network Issues 574
Viewing Network Performance 578
Reviewing the Network’s Configuration 584
Troubleshooting Storage Issues 587
Running Out of Filesystem Space 587
Waiting on Disk I/O 588
Measuring Disk Performance 591
Failing Disks 593
Troubleshooting the CPU 594
Troubleshooting Memory 595
Swapping 596
Running Out of Memory 599
Surviving a Lost Root Password 600
Summary 601
Exam Essentials 601
Review Questions 603
Chapter 21 Optimizing Performance 607
Looking at Processes 608
Monitoring Processes in Real Time 610
Managing Processes 614
Setting Priorities 614
Stopping Processes 615
Summary 618
Exam Essentials 619
Review Questions 620
Chapter 22 Investigating User Issues 623
Troubleshooting Access 624
Local 624
Remote 629
Authentication 630
Examining File Obstacles 631
File Permissions 631
Directory Permissions 632
Working with Advanced Permissions 633
File Creation 635
Exploring Environment and Shell Issues 636
Summary 638
Exam Essentials 638
Review Questions 639
Chapter 23 Dealing with Linux Devices 643
Communicating with Linux Devices 644
Device Interfaces 644
The /dev Directory 647
The /proc Directory 648
The /sys Directory 650
Working with Devices 651
Finding Devices 651
Working with PCI Devices 654
Working with USB Devices 655
Supporting Monitors 656
Using Printers 658
Using Hot-Pluggable
Devices 659
Detecting Dynamic Devices 660
Working with Dynamic Devices 660
Summary 662
Exam Essentials 662
Review Questions 664
Chapter 24 Troubleshooting Application and Hardware Issues 667
Dealing with Storage Problems 668
Exploring Common Issues 668
Dealing with Specialized Issues 670
Uncovering Application Permission Issues 674
Analyzing Application Dependencies 677
Versioning 677
Updating Issues 677
Patching 678
Dealing with Libraries 679
Exploring Environment Variable Issues 679
Gaining GCC Compatibility 680
Perusing Repository Problems 680
Looking at SELinux Context Violations 681
Exploring Firewall Blockages 682
Unrestricting ACLs 682
Unblocking Ports 683
Unblocking Protocols 683
Troubleshooting Additional Hardware Issues 684
Looking at Helpful Hardware Commands 684
Investigating Other Hardware Problems 688
Summary 692
Exam Essentials 692
Review Questions 694
Part VI Automating Your System 697
Chapter 25 Deploying Bash Scripts 699
The Basics of Shell Scripting 700
Running Multiple Commands 700
Redirecting Output 701
Piping Data 702
The Shell Script Format 703
Running the Shell Script 704
Advanced Shell Scripting 705
Displaying Messages 706
Using Variables 706
Command-Line
Arguments 709
The Exit Status 710
Writing Script Programs 711
Command Substitution 711
Performing Math 712
Logic Statements 714
Loops 717
Text Manipulation 720
Summary 721
Exam Essentials 722
Review Questions 724
Chapter 26 Automating Jobs 727
Running Scripts in Background Mode 728
Running in the Background 728
Running Multiple Background Jobs 729
Running Scripts without a Console 730
Sending Signals 732
Interrupting a Process 732
Pausing a Process 732
Job Control 734
Viewing Jobs 734
Restarting Stopped Jobs 736
Running Like Clockwork 737
Scheduling a Job Using the at Command 737
Scheduling Regular Scripts 740
Summary 744
Exam Essentials 744
Review Questions 746
Chapter 27 Controlling Versions with Git 749
Understanding Version Control 750
Setting Up Your Git Environment 752
Committing with Git 755
Tags 762
Merging Versions 763
Summary 766
Exam Essentials 766
Review Questions 768
Part VII Realizing Virtual and Cloud Environments 771
Chapter 28 Understanding Cloud and Virtualization
Concepts 773
Considering Cloud Services 774
What Is Cloud Computing? 774
What Are the Cloud Services? 775
Understanding Virtualization 777
Hypervisors 778
Types of Hypervisors 779
Hypervisor Templates 781
Exploring Containers 781
What Are Containers? 781
Container Software 782
Container Templates 783
Working with Docker 783
Summary 786
Exam Essentials 787
Review Questions 788
Chapter 29 Inspecting Cloud and Virtualization Services 791
Focusing on VM Tools 792
Looking at libvirt 792
Viewing virsh 793
Managing with Virtual Machine Manager 794
Understanding Bootstrapping 796
Booting with Shell Scripts 796
Kickstarting with Anaconda 797
Initializing with Cloud-init 801
Exploring Storage Issues 802
Considering Network Configurations 804
Virtualizing the Network 804
Configuring Virtualized NICs 805
Summary 808
Exam Essentials 808
Review Questions 810
Chapter 30 Orchestrating the Environment 813
Understanding Orchestration Concepts 814
Probing Procedures 815
Analyzing Attributes 816
Provisioning the Data Center 819
Coding the Infrastructure 819
Automating the Infrastructure 820
Comparing Agent and Agentless 821
Investigating the Inventory 821
Looking at Container Orchestration Engines 822
Embracing Kubernetes 822
Inspecting Docker Swarm 823
Surveying Mesos 823
Summary 823
Exam Essentials 824
Review Questions 825
Appendix Answers to the Review Questions 829
Chapter 2: Introduction to Services 830
Chapter 3: Managing Files, Directories, and Text 833
Chapter 4: Searching and Analyzing Text 837
Chapter 5: Explaining the Boot Process 841
Chapter 6: Maintaining System Startup and Services 844
Chapter 7: Configuring Network Connections 848
Chapter 8: Comparing GUIs 851
Chapter 9: Adjusting Localization Options 855
Chapter 10: Administering Users and Groups 858
Chapter 11: Handling Storage 861
Chapter 12: Protecting Files 863
Chapter 13: Governing Software 864
Chapter 14: Tending Kernel Modules 866
Chapter 15: Applying Ownership and Permissions 868
Chapter 16: Looking at Access and Authentication Methods 869
Chapter 17: Implementing Logging Services 871
Chapter 18: Overseeing Linux Firewalls 872
Chapter 19: Embracing Best Security Practices 874
Chapter 20: Analyzing System Properties and Remediation 876
Chapter 21: Optimizing Performance 878
Chapter 22: Investigating User Issues 880
Chapter 23: Dealing with Linux Devices 881
Chapter 24: Troubleshooting Application and Hardware Issues 883
Chapter 25: Deploying Bash Scripts 885
Chapter 26: Automating Jobs 887
Chapter 27: Controlling Versions with Git 889
Chapter 28: Understanding Cloud and Virtualization Concepts 890
Chapter 29: Inspecting Cloud and Virtualization Services 892
Chapter 30: Orchestrating the Environment 894
Index 897
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