CompTIA Linux+ Study Guide with Online Labs (4^th Ed.)
Exam XK0-004

Virtual, hands-on learning labs allow you to apply your technical skills using live hardware and software hosted in the cloud. So Sybex has bundled CompTIA Linux+ labs from Practice Labs, the IT Competency Hub, with our popular CompTIA Linux+ Study Guide, Fourth Edition. Working in these labs gives you the same experience you need to prepare for the CompTIA Linux+ Exam XK0-004 that you would face in a real-life setting. Used in addition to the book, the labs are a proven way to prepare for the certification and for work in the IT and cybersecurity fields where Linux is fundamental to modern systems and security.

This is your one-stop resource for complete coverage of Exam XK0-004, covering 100% of all exam objectives. You'll prepare for the exam smarter and faster with Sybex thanks to superior content including, assessment tests that check exam readiness, objective map, real-world scenarios, hands-on exercises, key topic exam essentials, and challenging chapter review questions. 

Linux is viewed by many organizations and companies as an excellent, low-cost, secure alternative to expensive OSs, such as Microsoft Windows and is crucial to today's server and cloud infrastructure. The CompTIA Linux+ exam tests a candidate's understanding and familiarity with the Linux. As the Linux server market share continues to grow, so too does demand for qualified and certified Linux administrators.

Building on the popular Sybex Study Guide approach, this book will provide 100% coverage of the NEW Linux+ Exam XK0-004 objectives. The book contains clear and concise information on all Linux administration topic, and includes practical examples and insights drawn from real-world experience.

• Hardware and System Configuration
• Systems Operation and Maintenance
• Security
• Linux Troubleshooting and Diagnostics
• Automation and Scripting

You'll also have access to an online test bank, including a bonus practice exam, electronic flashcards, and a searchable PDF of key terms.

And with this edition you also get Practice Labs virtual labs that run from your browser. The registration code is included with the book and gives you 6 months unlimited access to Practice Labs CompTIA Linux+ Exam XK0-004 Labs with 65 unique lab modules to practice your skills.

Introduction xxix

Assessment Test xlii

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 CentOS 9

Looking at Ubuntu 10

Looking at openSUSE 12

Looking at Fedora 13

Locating a Terminal 14

Summary 14

Chapter 2 Sifting Through Services 15

What is a Linux Server? 16

Launching Services 17

Listening for Clients 18

Serving the Basics 19

Web Servers 20

Database Servers 21

Mail Servers 22

Serving Local Networks 24

File Servers 25

Print Servers 26

Network Resource Servers 26

Implementing Security 29

Authentication Server 29

Certificate Authority 30

Access Server (SSH) 31

Virtual Private Networks 31

Proxy Server 32

Monitoring 32

Improving Performance 32

Clustering 32

Load Balancing 33

Containers 33

Summary 33

Exam Essentials 34

Review Questions 35

Chapter 3 Managing Files, Directories, and Text 39

Handling Files and Directories 40

Viewing and Creating Files 40

Copying and Moving Files 45

Removing Files 52

Linking Files and Directories 55

Establishing a Hard Link 55

Constructing a Soft Link 57

Reading Files 59

Reading Entire Text Files 59

Reading Text File Portions 61

Reading Text File Pages 65

Finding Information 66

Exploring File Differences 67

Using Simple Pinpoint Commands 69

Using Intricate Pinpoint Commands 73

Summary 77

Exam Essentials 77

Review Questions 78

Chapter 4 Searching and Analyzing Text 83

Processing Text Files 84

Filtering Text 84

Formatting Text 89

Determining Word Count 93

Redirecting Input and Output 95

Handling Standard Output 95

Redirecting Standard Error 96

Regulating Standard Input 98

Piping Commands 100

Creating Here Documents 102

Creating Command Lines 103

Editing Text Files 105

Appreciating Text Editors 105

Learning About Stream Editors 110

Summary 116

Exam Essentials 117

Review Questions 118

Part II Starting Up and Configuring Your System 123

Chapter 5 Explaining the Boot Process 125

The Linux Boot Process 126

Following the Boot Process 126

Viewing the Boot Process 127

The Firmware Startup 128

The BIOS Startup 128

The UEFI Startup 129

Linux Bootloaders 130

GRUB Legacy 131

GRUB2 134

Alternative Bootloaders 136

System Recovery 137

Kernel Failures 137

Root Drive Failure 139

Summary 141

Exam Essentials 141

Review Questions 143

Chapter 6 Maintaining System Startup and Services 147

Looking at init 148

Managing systemd Systems 149

Exploring Unit Files 150

Focusing on Service Unit Files 152

Focusing on Target Unit Files 157

Looking at systemctl 159

Examining Special systemd Commands 162

Managing SysV init Systems 167

Understanding Runlevels 168

Investigating SysV init Commands 171

Digging Deeper into systemd 176

Looking at systemd Mount Units 176

Exploring Automount Units 178

Summary 179

Exam Essentials 179

Review Questions 181

Chapter 7 Configuring Network Connections 187

Configuring Network Features 188

Network Configuration Files 188

Graphical Tools 191

Command-Line Tools 193

Basic Network Troubleshooting 201

Sending Test Packets 201

Finding Host Information 202

Advanced Network Troubleshooting 205

The netstat Command 205

Examining Sockets 208

Summary 209

Exam Essentials 210

Review Questions 212

Chapter 8 Comparing GUIs 217

Focusing on the GUI 218

Getting to Know GNOME 219

Probing KDE Plasma 221

Considering Cinnamon 223

Making Acquaintance with MATE 225

Understanding Unity 227

Setting Up Accessibility 228

Serving Up the GUI 231

Figuring Out Wayland 232

Examining X11 234

Using Remote Desktops 235

Viewing VNC 236

Grasping Xrdp 238

Exploring NX 239

Studying SPICE 240

Forwarding 240

Local 242

Remote 243

Tunneling Your X11 Connection 244

Summary 245

Exam Essentials 245

Review Questions 247

Chapter 9 Adjusting Localization Options 253

Understanding Localization 254

Character Sets 254

Environment Variables 255

Setting Your Locale 256

Installation Locale Decisions 256

Changing Your Locale 257

Looking at Time 259

Working with Time Zones 259

Setting the Time and Date 260

Watching System Time 264

Summary 265

Exam Essentials 266

Review Questions 267

Part III Managing Your System 273

Chapter 10 Administering Users and Groups 275

Managing User Accounts 276

Adding Accounts 276

Maintaining Passwords 288

Modifying Accounts 290

Deleting Accounts 292

Managing Groups 294

Setting Up the Environment 297

Perusing Bash Parameters 298

Understanding User Entries 299

Grasping Global Entries 300

Querying Users 300

Exploring the whoami Utility 300

Understanding the who Utility 301

Identifying with the id Program 302

Displaying Access History with the last Utility 303

Managing Disk Space Usage 304

Summary 308

Exam Essentials 308

Review Questions 310

Chapter 11 Handling Storage 315

Storage Basics 316

Drive Connections 316

Partitioning Drives 317

Automatic Drive Detection 317

Partitioning Tools 318

Working with fdisk 318

Working with gdisk 320

The GNU parted Command 322

Graphical Tools 322

Understanding Filesystems 323

The Virtual Directory 324

Maneuvering Around the Filesystem 326

Formatting Filesystems 326

Common Filesystem Types 326

Creating Filesystems 328

Mounting Filesystems 329

Manually Mounting Devices 329

Automatically Mounting Devices 330

Managing Filesystems 331

Retrieving Filesystem Stats 331

Filesystem Tools 332

Storage Alternatives 333

Multipath 333

Logical Volume Manager 334

Using RAID Technology 336

Summary 338

Exam Essentials 338

Review Questions 340

Chapter 12 Protecting Files 343

Understanding Backup Types 344

Looking at Compression Methods 346

Comparing Archive and Restore Utilities 349

Copying with cpio 349

Archiving with tar 352

Duplicating with dd 357

Replicating with rsync 359

Securing Offsite/Off-System Backups 362

Copying Securely via scp 362

Transferring Securely via sftp 363

Checking Backup Integrity 366

Digesting an MD5 Algorithm 366

Securing Hash Algorithms 367

Summary 368

Exam Essentials 368

Review Questions 370

Chapter 13 Governing Software 373

Working with Source Code 374

Downloading Source Code 374

Bundling Source Code Packages 375

Compiling Source Code 379

Packaging Applications 380

Installing and Managing Packages 381

Understanding Repositories 385

Summary 392

Exam Essentials 393

Review Questions 394

Chapter 14 Tending Kernel Modules 397

Exploring Kernel Modules 398

Installing Kernel Modules 402

Removing Kernel Modules 404

Summary 405

Exam Essentials 405

Review Questions 407

Part IV Securing Your System 409

Chapter 15 Applying Ownership and Permissions 411

Looking at File and Directory Permissions 412

Understanding Ownership 412

Controlling Access Permissions 414

Exploring Special Permissions 417

Managing Default Permissions 418

Access Control Lists 420

Context-Based Permissions 422

Using SELinux 423

Using AppArmor 427

Understanding Linux User Types 430

Types of User Accounts 430

Escalating Privileges 430

Restricting Users 431

Summary 435

Exam Essentials 436

Review Questions 437

Chapter 16 Looking at Access and Authentication Methods 439

Getting to Know PAM 440

Exploring PAM Configuration Files 440

Enforcing Strong Passwords 444

Locking Out Accounts 447

Limiting Root Access 451

Exploring PKI Concepts 452

Getting Certificates 453

Discovering Key Concepts 453

Securing Data 454

Signing Transmissions 455

Using SSH 455

Exploring Basic SSH Concepts 456

Configuring SSH 458

Generating SSH Keys 460

Authenticating with SSH Keys 462

Authenticating with the Authentication Agent 464

Using SSH Securely 466

Using VPN as a Client 468

Summary 469

Exam Essentials 469

Review Questions 471

Chapter 17 Implementing Logging Services 473

Understanding the Importance of Logging 474

The syslog Protocol 474

The History of Linux Logging 476

Basic Logging Using rsyslog 477

Configuration 477

Making Log Entries 479

Finding Event Messages 479

Journaling with systemd-journald 480

Configuration 480

Viewing Logs 481

Summary 483

Exam Essentials 484

Review Questions 485

Chapter 18 Overseeing Linux Firewalls 487

Providing Access Control 488

Looking at Firewall Technologies 490

Familiarizing Yourself with firewalld 491

Investigating iptables 495

Understanding UFW 500

Forwarding IP Packets 505

Dynamically Setting Rules 506

DenyHosts 506

Fail2ban 506

IPset 507

Summary 508

Exam Essentials 508

Review Questions 510

Chapter 19 Embracing Best Security Practices 513

User Security 514

Authentication Methods 514

Multifactor Authentication 516

Unique User Accounts 517

Restricting the root Account 517

System Security 518

Separation of Data 518

Disk Encryption 519

Restricting Applications 520

Preventing Unauthorized Rebooting 520

Restricting Unapproved Jobs 522

Banners and Messages 523

Restricting USB Devices 523

Looking for Trouble 524

Auditing 524

Network Security 525

Denying Hosts 525

Disabling Unused Services 525

Changing Default Ports 526

Using Encryption on the Network 526

Summary 528

Exam Essentials 528

Review Questions 530

Part V Troubleshooting Your System 533

Chapter 20 Analyzing System Properties and Remediation 535

Troubleshooting the Network 536

Exploring Network Issues 536

Viewing Network Performance 540

Reviewing the Network’s Configuration 546

Troubleshooting Storage Issues 549

Running Out of Filesystem Space 549

Waiting on Disk I/O 550

Failing Disks 553

Troubleshooting the CPU 554

Troubleshooting Memory 556

Swapping 556

Running Out of Memory 560

Surviving a Lost root Password 560

Summary 562

Exam Essentials 562

Review Questions 563

Chapter 21 Optimizing Performance 567

Looking at Processes 568

Monitoring Processes in Real Time 570

Managing Processes 573

Setting Priorities 574

Stopping Processes 574

Summary 577

Exam Essentials 577

Review Questions 579

Chapter 22 Investigating User Issues 581

Troubleshooting Access 582

Local 582

Remote 586

Authentication 587

Examining File Obstacles 588

File Permissions 588

Directory Permissions 589

File Creation 590

Exploring Environment and Shell Issues 591

Summary 593

Exam Essentials 593

Review Questions 594

Chapter 23 Dealing with Linux Devices 597

Communicating with Linux Devices 598

Device Interfaces 598

The /dev Directory 600

The /proc Directory 601

The /sys Directory 604

Working with Devices 605

Finding Devices 605

Working with PCI Cards 608

Working with USB Devices 609

Supporting Monitors 610

Using Printers 611

Using Hot Pluggable Devices 613

Detecting Dynamic Devices 613

Working with Dynamic Devices 614

Summary 615

Exam Essentials 616

Review Questions 617

Chapter 24 Troubleshooting Application and Hardware Issues 619

Dealing with Storage Problems 620

Exploring Common Issues 620

Dealing with Specialized Issues 622

Uncovering Application Permission Issues 626

Analyzing Application Dependencies 628

Versioning 629

Updating Issues 629

Patching 630

Dealing with Libraries 630

Exploring Environment Variable Issues 631

Gaining GCC Compatibility 631

Perusing Repository Problems 632

Looking at SELinux Context Violations 633

Exploring Firewall Blockages 633

Unrestricting ACLs 633

Unblocking Ports 634

Unblocking Protocols 635

Troubleshooting Additional Hardware Issues 635

Looking at Helpful Hardware Commands 635

Investigating Other Hardware Problems 639

Summary 643

Exam Essentials 643

Review Questions 645

Part VI Automating Your System 649

Chapter 25 Deploying Bash Scripts 651

The Basics of Shell Scripting 652

Running Multiple Commands 652

Redirecting Output 653

Piping Data 654

The Shell Script Format 655

Running the Shell Script 656

Advanced Shell Scripting 657

Displaying Messages 657

Using Variables 658

Command-Line Arguments 661

The Exit Status 662

Writing Script Programs 663

Command Substitution 663

Performing Math 664

Logic Statements 666

Loops 669

Summary 673

Exam Essentials 674

Review Questions 675

Chapter 26 Automating Jobs 677

Running Scripts in Background Mode 678

Running in the Background 678

Running Multiple Background Jobs 679

Running Scripts Without a Console 680

Sending Signals 681

Interrupting a Process 682

Pausing a Process 682

Job Control 683

Viewing Jobs 683

Restarting Stopped Jobs 686

Running Like Clockwork 687

Scheduling a Job Using the at Command 687

Scheduling Regular Scripts 690

Summary 692

Exam Essentials 693

Review Questions 694

Chapter 27 Controlling Versions with Git 697

Understanding Version Control 698

Setting Up Your Git Environment 700

Committing with Git 703

Merging Versions 710

Summary 713

Exam Essentials 713

Review Questions 715

Part VII Realizing Virtual and Cloud Environments 717

Chapter 28 Understanding Cloud and Virtualization Concepts 719

Considering Cloud Services 720

What is Cloud Computing? 720

What Are the Cloud Services? 721

Understanding Virtualization 723

Hypervisors 723

Types of Hypervisors 725

Hypervisor Templates 726

Exploring Containers 727

What Are Containers? 727

Container Software 728

Container Templates 729

Exercise 729

Summary 730

Exam Essentials 731

Review Questions 732

Chapter 29 Inspecting Cloud and Virtualization Services 735

Focusing on VM Tools 736

Looking at libvirt 736

Viewing virsh 737

Managing with Virtual Machine Manager 738

Understanding Bootstrapping 740

Booting with Shell Scripts 740

Kick-Starting with Anaconda 741

Initializing with Cloud-init 744

Exploring Storage Issues 746

Considering Network Configurations 747

Virtualizing the Network 747

Configuring Virtualized NICs 748

Summary 750

Exam Essentials 751

Review Questions 752

Chapter 30 Orchestrating the Environment 755

Understanding Orchestration Concepts 756

Probing Procedures 757

Analyzing Attributes 758

Provisioning the Data Center 760

Coding the Infrastructure 761

Automating the Infrastructure 762

Comparing Agent and Agentless 762

Investigating the Inventory 763

Looking at Container Orchestration Engines 763

Embracing Kubernetes 763

Inspecting Docker Swarm 764

Surveying Mesos 764

Summary 765

Exam Essentials 765

Review Questions 766

Appendix Answers to Review Questions 769

Chapter 2: Sifting Through Services 770

Chapter 3: Managing Files, Directories, and Text 773

Chapter 4: Searching and Analyzing Text 777

Chapter 5: Explaining the Boot Process 781

Chapter 6: Maintaining System Startup and Services 784

Chapter 7: Configuring Network Connections 788

Chapter 8: Comparing GUIs 791

Chapter 9: Adjusting Localization Options 795

Chapter 10: Administering Users and Groups 798

Chapter 11: Handling Storage 801

Chapter 12: Protecting Files 803

Chapter 13: Governing Software 804

Chapter 14: Tending Kernel Modules 806

Chapter 15: Applying Ownership and Permissions 808

Chapter 16: Looking at Access and Authentication Methods 810

Chapter 17: Implementing Logging Services 811

Chapter 18: Overseeing Linux Firewalls 813

Chapter 19: Embracing Best Security Practices 815

Chapter 20: Embracing Best Security Practices 817

Chapter 21: Optimizing Performance 818

Chapter 22: Investigating User Issues 820

Chapter 23: Dealing with Linux Devices 822

Chapter 24: Troubleshooting Application and Hardware Issues 824

Chapter 25: Deploying Bash Scripts 826

Chapter 26: Automating Jobs 827

Chapter 27: Controlling Versions with Git 829

Chapter 28: Understanding Cloud and Virtualization Concepts 831

Chapter 29: Inspecting Cloud and Virtualization Services 832

Chapter 30: Orchestrating the Environment 834

Index 837

CHRISTINE BRESNAHAN, LINUX+, started working with computers more than 30 years ago as a system administrator. She is an Adjunct Professor at Ivy Tech Community College, where she teaches Linux Essentials, CompTIA Linux+ certification, and Python classes.

RICHARD BLUM, LINUX+, is a 30-year IT industry veteran, as both systems and network administrator for UNIX, Linux, and Microsoft servers. Rich is widely published on Linux and open source software and is an online Linux instructor for universities nationwide.