CompTIA Linux+ / LPIC-1 Cert Guide

Ross Brunson has more than 20 years of experience as a Linux and Open Source trainer, training manager, and technologist and is author of the popular LPIC-1 Exam Cram (QUE Publishing). Ross is currently senior training/certification engineer at SUSE and recently spent almost five years as the director of member services for the Linux Professional Institute, where he contributed to placing several LPI courses into the Cisco Networking Academy, conducted dozens of Train-the-Trainer sessions, and provided sales enablement support for the worldwide Master Affiliate network spanning more than 100 countries. Ross holds a number of key IT certifications and is also author of several successful technical books and dozens of technical courses for major organizations (including the first LPI Certification Bootcamps). He is skilled at both contributing to and building community around IT products. He lives in Paradise Valley, Montana, with his family and enjoys traveling far and wide, winter sports, and photography. Sean Walberg has more than 20 years of experience as a Linux administrator, network engineer, and software developer. He has written extensively on Linux certification for IBM and NetDevGroup, and has contributed to other books both as an author and technical reviewer. Sean currently works at Northfield IT and is responsible for infrastructure automation for a large professional sports league. Using tools like Ruby, shell scripts, and Chef, he automates the creation and maintenance of more than a thousand servers and the associated network infrastructure. Sean works closely with developers to scale applications to the demands of an internationally recognized series of web properties. He lives in Northern Virginia with his wife and three sons.

Chapter 1 Installing Linux 3
“Do I Know This Already?” Quiz 3
Understanding Your Hardware 6
     Peripheral Compatibility 7
     Enumerating Your Peripherals 7
     The Proc Filesystem 8
          Friends of procfs 10
          Dealing with Integrated Peripherals 10
Laying Out the Hard Drive 11
     Partitions and Devices 11
     The Root Filesystem 12
     Logical Volume Manager (LVM) 14
     Commonly Used Mounts 16
     Swap Files 16
Working with Boot Managers 17
     GRUB Legacy 17
     GRUB2 18
          Installing GRUB2 18
          Using the GRUB2 Command Line 19
          Configuring GRUB2 20
Summary 21
Exam Preparation Tasks 22
     Review All Key Topics 22
     Define Key Terms 22
     Review Questions 23

Chapter 2 Boot Process and Runlevels 27
“Do I Know This Already?” Quiz 27
The Linux Boot Process 30
     What Is the Boot Process? 30
     Boot Loaders 30
     Common Commands at Boot Time 32
Boot Sequence from BIOS to Fully Running System 33
     SysVinit 33
systemd 34
     Units in systemd 36
     systemd Targets and Runlevels 37
     Wants and Requires 38
Booting with systemd 38
     Upstart 39
          Managing System Runlevels 40
          Determining the Default Runlevel 40
     Setting the Default Runlevels 41
     Changing Runlevels 41
Shut Down and Reboot from the Command Line 42
     Alerting Users 43
Properly Terminating Processes 44
     kill and killall 44
     Reloading or “Hanging Up” Processes 45
Logging Boot Events 45
Exam Preparation Tasks 46
     Review All Key Topics 46
     Define Key Terms 47
     Review Questions 47

Chapter 3 Package Install and Management 51
“Do I Know This Already?” Quiz 51
Software in a Linux System 54
     Shared Libraries 54
     Working with Shared Libraries 56
     Determining Required Libraries 56
          Looking for Libraries in Other Places 57
Debian Package Management 58
     Managing Local Debian Packages 58
          Installing Packages with dpkg 59
          Removing Packages 60
          Dependency Issues 60
          Querying Packages 61
          Reconfiguring Packages 63
     Using Remote Repositories 64
          Installing Remote Packages 64
          Working with the Cache 65
          Upgrading the System 66
          Removing Packages 67
          Graphical Managers 67
RPM and YUM Package Management 68
     The RPM Database 68
          RPM Package Files 69
          Package Name Conventions 69
     The rpm Command 70
          Validation of Packages 71
          Installation of Packages 72
          Additional Installation Options 72
          Verifying a Package’s Integrity 73
          Freshening Versus Upgrading 74
          Removing Packages 75
          Other Removal Options 76
     Querying Packages 77
     Package Management with YUM 80
          Installing Packages 80
          Fetching Updates 83
          Finding Packages to Install 83
     Configuring Yum 84
Summary 86
Exam Preparation Tasks 86
     Review All Key Topics 86
     Define Key Terms 87
     Review Questions 88

Chapter 4 Basic Command Line Usage 91
“Do I Know This Already?” Quiz 91
What Is a Shell? 93
Global and User Settings 94
     Sourcing Versus Executing 94
          Executing a Script 94
     Sourcing a Script 94
     A Login Shell Session 95
     A Non-Login Shell Session 96
Using the Command Line 97
     There Are Commands and, Well, Commands 97
     Structuring Commands 98
     Breaking Long Command Lines 98
     Command Completion 99
     Special Characters in the Shell 99
Controlling Command Execution 100
     Possible Exit Statuses 100
Environment Variables and Settings 101
     The Path 102
     Getting $HOME 102
     bash’s History Feature 103
     Important History Variables 104
Setting Options in bash 104
     Important bash Options 104
Exam Preparation Tasks 105
     Review All Key Topics 105
     Define Key Terms 106
     Review Questions 106

Chapter 5 File Management 109
“Do I Know This Already?” Quiz 109
Filesystem Overview 112
     What Belongs Where 112
          The Root of the System 112
          Classifying Data 113
          Where Programs Live 114
File Management Commands 114
     Tips for Working with Linux Files 115
     Basic Navigation 115
     Advanced Navigation 116
     Listing Files and Directories 116
     Determining File Types 118
     Touching Files 120
     Copying Files and Directories 121
     Moving Objects 123
     Transforming Data Formats 126
     Creating and Removing Directories 127
     Removing Objects 128
Where Are Those Files? 128
     Locating Files with Locate 128
     Finding Files 130
     Which Command Will Run? 132
     Researching a Command 132
     Linking Files 133
          Symbolic Links 134
          Hard Links 135
Backup Commands 136
     Using tar 137
     Taking Pity on the Unarchiver 139
          Useful Creation Options 140
          Listing Archive Files 140
          Using cpio 141
     Compression Utilities 143
Summary 144
Exam Preparation Tasks 144
     Review All Key Topics 144
     Define Key Terms 145
     Review Questions 146

Chapter 6 Text Processing/Advanced Command Line 151
“Do I Know This Already?” Quiz 151
Working with Input/Output Streams 154
     Standard In 154
     Standard Out 154
     Standard Error 155
     Redirection of Streams 156
9780789754554_book.indb vii 11/13/15 5:04 PM
viii CompTIA Linux+ / LPIC-1 Cert Guide
     Redirecting Standard Input 157
     Redirecting Standard Output 157
     Redirecting Standard Error 157
     Redirection Redux 158
Pipes 159
Executing Multiple Commands 161
     Multiple Command Operators 161
     Command Substitution 162
Splitting and Processing Streams 163
     Splitting Streams with the tee Command 163
     Processing Output with the xargs Command 163
Filters 165
     Sorting 165
     Numbering Lines 166
     Tabs 167
     Cutting Columns 168
     Pasting and Joining 168
     Unique Data 169
     Heads or Tails? 170
     Splitting Files 172
     When cat Goes Backward 173
     Viewing Binary Files Safely 173
Formatting Commands 174
     Translating Files 175
     He sed, She sed 176
     Getting a grep 178
          Examples of Using grep 179
     Expanding grep with egrep and fgrep 184
Using Regular Expressions and grep 185
Summary 188
Exam Preparation Tasks 188
     Review All Key Topics 188
     Define Key Terms 189
     Review Questions 189

Chapter 7 Process Management 193
“Do I Know This Already?” Quiz 193
Managing Processes 196
     Viewing Processes 196
     What’s the Diff? 197
     The free Command 198
     Blocks and Buffers 199
     Pages, Slabs, and Caches 199
     Interpreting Displayed Information from free 200
     System Uptime 201
Sending Signals to Processes 202
     Killing Processes by PID 203
     Killing Processes by Other Criteria 204
Job Control 205
Managing Process Priorities 207
Leaving Programs Running after Logout 209
     Using screen for Multiple Console Sessions 210
          Taking Control-a of screen Windows 211
          Creating Windows in screen 211
          Detaching and Reattaching from screen 212
          Locking Your Console via screen 213
Summary 213
Exam Preparation Tasks 214
     Review All Key Topics 214
     Define Key Terms 215
     Review Questions 215

Chapter 8 Editing Text 219
“Do I Know This Already?” Quiz 219
A Tour of the vim Editor 222
     The Message Line 222
     Editing in vi 222
          Opening a File for Editing 223
          Navigating Within a File 224
          Force Multipliers 225
          Undo Operations 225
          Saving Files 226
          Quitting vi 226
          Changing or Replacing Text 227
          Deleting Text and Lines 227
          The Cut, Copy, and Paste Commands 228
          Named and Unnamed Buffers 229
     Searching in vi 230
          Searching and Replacing 231
          Regular Expression Searches 231
     Options in vi 232
     Advanced vi 234
          Running External Commands in vi 234
          Joining Lines 234
          Split Windows 234
Exam Preparation Tasks 236
     Review All Key Topics 236
     Review Questions 236

Chapter 9 Partitions and Filesystems 241
“Do I Know This Already?” Quiz 241
Creating Partitions 244
     Partitions 244
     Swap 245
     Disk Partitioning Tools 245
          fdisk 246
          gdisk 250
          Parted 254
Filesystems 255
     Filesystem Types 255
     Superblocks 256
     Inodes and Files 256
     Inodes and Directories 258
     Inodes and Disk Space 259
     Creating Filesystems 260
          The mkfs Command 260
          Filesystem Creation Options 261
     Advanced Filesystem Commands 263
          Filesystem Checker 263
          Tuning Filesystems 266
          XFS Commands 267
          Debugging Filesystems 268
          Mounting and Unmounting 269
     The Filesystem Table 270
          Manually Mounting Filesystems 272
          Automatically Mounting Filesystems 273
          Unmounting Filesystems 273
Space Utilization 274
     Using du 274
     Using df 275
     Using Disk Quotas 277
          Quota Commands and Files 277
          Quota Concepts 277
          Configuring Quotas 278
          Hard and Soft Limits 280
          Setting the Grace Period 281
          Getting Quota Information 281
Summary 282
Exam Preparation Tasks 282
     Review All Key Topics 282
     Define Key Terms 284
     Review Questions 284

Chapter 10 Permissions and Ownership 289
“Do I Know This Already?” Quiz 289
Working with Permissions 292
     Permission Trio Bits 292
Manipulating Permissions 294
     Numeric Mode 294
          Symbolic Mode 296
Special File Permissions 297
     Special Bit Permissions 298
     Setting the SUID Bit on Files 299
     Setting the SGID Bit on Files 300
     Setting the SGID Bit on Directories 301
     Setting the Sticky Bit 302
Finding Files by Permission 302
Default Permissions 303
Changing User Ownership 305
Changing Group Ownership 306
Summary 307
Exam Preparation Tasks 307
     Review All Key Topics 307
     Define Key Terms 308
     Review Questions 308

Chapter 11 Customizing Shell Environments 311
“Do I Know This Already?” Quiz 311
Working Within the Shell 314
     Environment Variables 315
     Variable Scope 316
          Setting Variables from a Child 316
     Setting and Unsetting Variables 317
     Subshells 318
          The env Wrapper 319
Extending the Shell 320
     Global and User Settings 320
          A Login Shell Session 321
          A Non-Login Shell Session 321
     The PATH 322
          Aliases and Functions 323
          Functions 323
     PS1 324
          Adding More Dynamic Content 325
          PS2 326
     Creating New Users (skeleton) 326
Localization and Internationalization 327
     Time Zones 327
          Displaying Time 328
          Setting Time Zones 328
     Character Encoding 329
     Representing Locales 330
          Fallback Locales 331
     Contents of a Locale 331
     How Linux Uses the Locale 332
          Converting Files Between Encodings 334
Exam Preparation Tasks 334
     Review All Key Topics 334
     Define Key Terms 335
     Review Questions 335

Chapter 12 Shell Scripting 339
“Do I Know This Already?” Quiz 339
Basics of Scripting 342
     Running a Script 343
     Good Design 343
     Managing Your Scripts 344
Shell Script Commands 344
     Use the Output of Another Command 344
     Do Math 345
     Conditions 346
     Testing Files 348
     An Easier Test Syntax 348
     Testing Strings 349
     Testing Integers 350
     Combining Multiple Tests 351
     Case Statements 351
     Loops 353
          For Loops 353
          Sequences 354
          While Loops 355
          Reading from stdin in a Loop 356
     Interacting with Other Programs 356
     Returning an Error Code 357
     Accepting Arguments 357
     Transferring Control to Another Program 358
Exam Preparation Tasks 359
     Review All Key Topics 359
     Define Key Terms 360
     Review Questions 360

Chapter 13 Basic SQL Management 365
“Do I Know This Already?” Quiz 365
Database Basics 368
     Types of Databases 368
          Key-Value Databases 368
          Relational Databases 369
          Schemaless Databases 370
Learning SQL 371
     Using SQLite 371
     SQL Basics 372
          Keywords Versus Data 372
     Selecting Data 373
          Being Choosy 374
          Multiple Conditions 376
          Sorting 377
     Limiting Results 378
     Working with Multiple Tables 378
          Writing Queries with Joins 379
          Cleaning Up the Query 381
     Advanced Joins 381
          Left Versus Right Joins 384
          Null 384
     Subselects 385
     Grouping Data 386
     Inserting Data 387
     Updating Data 388
     Deleting Data 388
     Creating Tables 388
Summary 390
Exam Preparation Tasks 390
     Review All Key Topics 390
     Define Key Terms 391
     Review Questions 392

Chapter 14 Configuring User Interfaces and Desktops 397
“Do I Know This Already?” Quiz 397
Quick Overview of X 400
     How X Works 400
          Window Managers 401
          Linux Desktops 402
The Xorg System 402
     The Xorg Configuration File 402
     Fonts in X 405
     Tuning X 406
X Display Managers 408
Into and Out of X 409
Accessibility Options 410
     Sticky/Repeat Keys 410
     Slow/Bounce/Toggle Keys 411
     Mouse Keys 411
     High Contrast/Large Print Desktop Themes 412
     Screen Reader 412
     Braille Display 413
     Screen Magnifier 413
     Onscreen Keyboard 413
Remote Clients 413
Summary 415
Exam Preparation Tasks 415
     Review All Key Topics 415
     Define Key Terms 415
     Review Questions 416

Chapter 15 Managing Users and Groups 419
“Do I Know This Already?” Quiz 419
User Account Fundamentals 422
     What Accounts Are What? 422
          Normal User Accounts 423
          User Entries in /etc/passwd 423
          Special Login Files 424
Group Accounts 425
     Group Entries in /etc/group 427
     Group Passwords 427
Adding Users and Groups 428
     Adding Users with useradd 428
     The useradd Defaults 429
     Adding Groups with groupadd 431
Modifying Users and Groups 431
     Modifying User Accounts with usermod 431
     Modifying Groups with groupmod 432
Removing Users and Groups 433
     Removing Users 433
     Removing Groups 434
The Shadow Suite 435
     Encrypted Passwords and Shadow Fields 435
     shadow File Permissions 437
Changing Accounts 437
     Aging Passwords 438
     User Variables 440
Summary 440
Exam Preparation Tasks 441
     Review All Key Topics 441
     Define Key Terms 442
     Review Questions 442

Chapter 16 Schedule and Automate Tasks 445
“Do I Know This Already?” Quiz 445
The Cron System 447
     Configuring crontabs 447
          Using the crontab Command 447
          Matching Times 448
          Spelling Out Month and Day Names 449
          Making Multiple Matches 449
          Step Values 450
          Putting the crontab Together 450
          Issues About Path 450
          Dealing with Output 451
          Nicknames 452
     Other Files 452
          System crontabs 453
          Convenience crontabs 454
     Restricting Access 454
Anacron 455
Running Ad-hoc Jobs 456
     The at Command 456
     The batch Command 458
Summary 459
Exam Preparation Tasks 460
     Review All Key Topics 460
     Define Key Terms 460
     Review Questions 461

Chapter 17 Configuring Print and Email Services 465
“Do I Know This Already?” Quiz 465
Managing Printers and Printing 467
     The Print Spooler 467
          Network Printing Protocols 467
     The CUPS Daemon 468
          The CUPS Pipeline 468
     Configuring CUPS 470
     CUPS Maintenance 474
          Printer State 475
          Maintenance and Administration Pull-downs 476
          Administration Menu 476
          Jobs List 477
     Command Line Tools 477
          Legacy Tools 477
          lp/lpr 478
          lpstat 478
          lpq 479
          lprm 479
          CUPS Tools 480
          cupsaccept/cupsreject 480
          cupsenable/cupsdisable 481
          cupsctl 481
          Configuration Files 482
     Troubleshooting Printing 482
          Try Printing from the Command Line 482
          Was the Job Queued? 483
          Can CUPS Send the Job to the Printer? 483
          Turn On Debugging 483
Mail Transfer Agent Basics 484
     How Email Flows 484
          Mail User Agent 484
          Mail Transfer Agent 485
          The Language of Email 485
          Linux MTAs 486
          Domain Name System 487
          Mail Delivery Agent 488
          Mail Server 488
     Creating Aliases and Forwarding Email 489
          Committing Changes 489
          Other Types of Aliases 490
          User-Defined Forwarding 491
     Managing Queues 491
Summary 492
Exam Preparation Tasks 492
     Review All Key Topics 492
     Define Key Terms 493
     Review Questions 493

Chapter 18 Logging and Time Services 497
“Do I Know This Already?” Quiz 497
Maintain System Time 500
     Not One, But Two Clocks 500
     Working with the System Clock 500
     Working with the Hardware Clock 503
          The hwclock Command 503
          Synchronizing Time Between Clocks 504
     Network Time Protocol 504
          Setting the Time from the Command Line 505
          The pool.ntp.org Servers 505
          Configuring ntpd 506
          Monitoring ntpd 507
System Logging 508
     systemd and syslog 508
          syslog 509
          The logger Command 512
          Configuring syslogd 512
          Other syslog Implementations 514
     systemd Logging 514
          Querying the Log 515
          Configuring journald 519
Rotating Logs 520
     Configuring Log Rotation 520
     Dealing with Open Files 522
Summary 522
Exam Preparation Tasks 523
     Review All Key Topics 523
     Define Key Terms 524
     Review Questions 524

Chapter 19 Networking Fundamentals 529
“Do I Know This Already?” Quiz 529
Conceptual Overview of Networking 532
     Necessary Configuration Information 533
     IP Addresses 533
     Networks and Hosts 534
     Address Class Ranges 534
          Using the Bits to Determine Class 535
     Network Masks 536
     Using Default Network Masks 536
     Gateway Addresses, or “Do I Dial with the Area Code?” 537
     Broadcast Addresses 538
     Custom Network Masks 538
     Determining a Custom Network Mask 538
     Additional Protocols 541
          Common Ports 542
     IPv6 544
Managing Interfaces 545
     Viewing IP Information 545
     Red Hat Interface Configuration 547
     Debian Interface Configuration 548
     Viewing and Configuring Gateway Addresses 550
          Viewing the Default Gateway 550
          Configuring a Default Gateway 550
          Local Name Configuration 551
Network Configuration Utilities 553
     Network Utility Examples 554
          The ifconfig Command 555
          The route Command 555
          DHCP Client Tools 556
          The host, getent, and dig Commands 557
          Hostname Utilities 559
          Using netstat 559
          The ping Command 562
          Using traceroute 563
          Using tcpdump 565
Summary 566
Exam Preparation Tasks 566
     Review All Key Topics 566
     Define Key Terms 567
     Review Questions 567

Chapter 20 System Security 571
“Do I Know This Already?” Quiz 571
Gaining Access to the root Account 574
     The su Command 574
     The sudo Command 575
Providing Services on Demand 576
     Using inetd and xinetd 576
     inetd Configuration Files 577
     xinetd Configuration Files 578
Using TCP Wrappers for Securing Services 581
     inetd and TCP Wrappers 581
     xinetd and TCP Wrappers 582
     The hosts.allow and hosts.deny Files 582
     Wrapper Read Order 583
     Format of hosts.allow and hosts.deny 583
     Sample Configurations 583
     Using Rule Options 585
Understanding Permission Problems 586
     Finding Files by Permissions 587
GnuPG Keys 587
Secure Shell 590
     SSH Components 591
          Using SSH Client Utilities 592
Additional Security Features 596
Summary 597
Exam Preparation Tasks 598
     Review All Key Topics 598
     Define Key Terms 599
     Review Questions 599

Chapter 21 Final Preparation 603
How to Prepare for the LPI Exams 604
     Caveat and Warning 604
     Exam Objectives 604
     Important Exam Facts 605
     Right Before Your Exam Starts 605
     How to Look at the Objectives 606
     Studying for the Exams—What to Do 608
     Machines or Virtual Machines? 609
     Studying for the Exams—What Not to Do 609
     Don’t Believe Everything 610
     Don’t Worry, Be Happy 610
     LPI Certifications and Distributions 610
     You Have to Install Something 611
     LPI Exam Question Types 611
     Single Answer Multiple Choice 612
     Choose Two/Choose Three 613
     Choose All That Apply 613
     Fill in the Blank 615
     Final Recommendations 616
Summary 617

Appendix A Answers to the “Do I Know This Already?” Quizzes and Review Questions 619

Glossary 659

Index 693