William “Bo” Rothwell At the impressionable age of 14, William “Bo” Rothwell crossed paths with a TRS-80 Micro Computer System (affectionately known as a “Trash 80”). Soon after the adults responsible for Bo made the mistake of leaving him alone with the TRS-80, he immediately dismantled it and held his first computer class, showing his friends what made this “computer thing” work.

Since this experience, Bo’s passion for understanding how computers work and sharing this knowledge with others has resulted in a rewarding career in IT training. His experience includes Linux, Unix, and programming languages such as Perl, Python, Tcl, and BASH. He is the founder and president of One Course Source, an IT training organization.

Denise Kinsey, Ph.D, CISSP, CISCO Dr. Denise Kinsey served as a Unix administrator (HP-UX) in the late 1990s and realized the power and flexibility of the operating system. This appreciation led to her home installation of different flavors of Linux and creation of several academic courses in Linux. With a strong background in cybersecurity, she works to share and implement best practices with her customers and students. Dr. Kinsey is an assistant professor at the University of Houston.

Introduction xxix
Part I: Introducing Linux 2
Chapter 1 Distributions and Key Components 4
Introducing Linux 4
Linux Distributions 5
Shells 6
GUI Software 7
Installing Linux 7
Which Distro? 8
Native or Virtual Machine? 9
Installing a Distro 10
Summary 12
Key Terms 12
Review Questions 12
Chapter 2 Working on the Command Line 14
File Management 14
The Linux Filesystem 14
Command Execution 16
The pwd Command 16
The cd Command 16
The ls Command 17
File Globbing 18
The file Command 19
The less Command 19
The head Command 19
The tail Command 20
The mdkir Command 20
The cp Command 20
The mv Command 21
The rm Command 21
The rmdir Command 22
The touch Command 22
Shell Features 22
Shell Variables 22
Initialization Files 27
Alias 28
Command History 29
Redirecting Input and Output 30
Advanced Commands 33
The find Command 33
Regular Expressions 35
The grep Command 36
The sed Command 37
Compression Commands 38
Summary 40
Key Terms 40
Review Questions 41
Chapter 3 Getting Help 42
Man Pages 42
Man Page Components 42
Man Page Sections 43
Man Page Locations 46
Command Help Options 46
The help Command 46
The info Command 47
The /usr/share/doc Directory 48
Internet Resources 49
Summary 50
Key terms 50
Review Questions 51
Chapter 4 Editing Files 52
The vi Editor 52
What Is vim? 53
Essential vi Commands 54
Use Basic vi Modes 54
Entering the Insert Mode 55
Movement Commands 56
Repeater Modifiers 57
Undoing 57
Copying, Deleting, and Pasting 58
Finding Text 59
Find and Replace 60
Saving and Quitting 61
Expand Your vi Knowledge 62
Additional Editors 63
Emacs 63
gedit and kwrite 65
nano and joe 65
lime and bluefish 65
Summary 66
Key Terms 66
Review Questions 66
Chapter 5 When Things Go Wrong 68
The Science of Troubleshooting 68
Step 1: Gathering Information 69
Step 2: Determine the Likely Cause 70
Step 3: Document Your Plan of Attack (POA) 71
Step 4: Perform the Actions 71
Steps 5 and 6: Is the Problem Solved? 71
Step 7: Are There Other Problems? 71
Step 8: Store the Documentation 72
Step 9: Prevent Future Problems 72
Notifying Users 72
Pre- and Post-login Messages 72
Broadcasting Messages 77
Summary 79
Review Questions 79
Part II: User and Group Accounts 80
Chapter 6 Managing Group Accounts 82
What Are Groups Used For? 82
Primary versus Secondary Groups 82
The /etc/group File 84
Special Groups 85
User Private Groups 86
The /etc/gshadow File 88
Managing Groups 90
Creating Groups 90
Modifying Groups 91
Deleting Groups 91
Adding Users to Groups 92
Group Administrators 93
Summary 93
Key Terms 93
Review Questions 94
Chapter 7 Managing User Accounts 96
The Importance of User Accounts 96
User Account Information 96
The /etc/passwd File 97
Special Users 98
The /etc/shadow File 99
Managing Users 102
Creating Users 102
Modifying Users 105
Managing GECOS 105
Deleting Users 107
Restricted Shell Accounts 107
Network-Based User Accounts 108
Using su and sudo 108
Restricting User Accounts 111
Summary 116
Key Terms 116
Review Questions 117
Chapter 8 Develop an Account Security Policy 118
Introducing Kali Linux 118
Security Principles 119
Creating a Security Policy 120
Securing Accounts 120
Physical Security 120
Educating Users 121
Account Security 121
Security Tools 124
The john and Johnny Tools 124
The hydra tool 125
Summary 126
Review Questions 126
Part III File and Data Storage 128
Chapter 9 File Permissions 130
Standard Permissions 130
Viewing Permissions 130
Files Versus Directories 131
Changing Permissions 131
Default Permissions 132
Special Permissions 134
SUID 134
SGID 136
Sticky Bit 138
Access Control Lists (ACLs) 139
The mask Value 141
Default ACLs 141
Changing Ownership 143
chown 143
chgrp 144
File Attributes 145
Introduction to SELinux 146
Users Create Security Holes 146
Daemon Processes Create Security Holes 146
SELinux Essentials 147
Summary 149
Key Terms 150
Review Questions 150
Chapter 10 Manage Local Storage: Essentials 152
Filesystem Essentials 152
Partitions 152
Filesystems 153
Why So Many Partitions/Filesystems? 154
Which Partitions/Filesystems Should Be Created? 155
Filesystem Types 155
Managing Partitions 156
Ext-Based Filesystem Tools 161
Xfs-Based Filesystem Tools 166
Additional Filesystem Tools 170
du 170
df 170
Mounting Filesystems 170
The umount Command 171
The mount Command 171
Mounting Filesystems Manually 173
Problems Unmounting Filesystems 174
Mounting Filesystems Automatically 175
Device Descriptors 176
Mount Options 177
Mounting Removable Media 179
Swap Space 179
Creating Swap Devices 180
Summary 181
Key Terms 181
Review Questions 181
Chapter 11 Manage Local Storage: Advanced Features 184
Encrypted Filesystems 184
Managing autofs 186
Logical Volume Manager 189
Logical Volume Manager Concepts 190
LVM Essentials 192
Using Logical Volumes and Additional LVM Commands 197
Resizing Logical Volumes 201
LVM Snapshots 204
Disk Quotas 206
Setting Up a Disk Quota for a Filesystem 207
Editing, Checking, and Generating User Quota Reports 207
Hard and Soft Links 210
Why Use Links? 211
Creating Links 211
Displaying Linked Files 212
Summary 212
Key Terms 212
Review Questions 212
Chapter 12 Manage Network Storage 214
Samba 214
SAMBA Configuration 215
SAMBA Server 218
SAMBA Accounts 220
Accessing SAMBA Servers 221
Network File System 223
Configuring an NFS Server 224
Configuring an NFS Client 229
iSCSI 230
Summary 236
Key Terms 236
Review Questions 236
Chapter 13 Develop a Storage Security Policy 240
Developing the Plan 240
Backing Up Data 241
Creating a Backup Strategy 241
Standard Backup Utilities 246
Third-party Backup Utilities 250
Summary 250
Key Terms 251
Review Questions 251
Part IV: Automation 252
Chapter 14 crontab and at 254
Using crontab 254
Configure User Access to the cron Service 256
/etc/crontab 258
/etc/anacrontab 260
Using at 261
atq 261
atrm 262
Configure User Access to at Services 262
Summary 263
Key Terms 263
Review Questions 263
Chapter 15 Scripting 264
Linux Programming 264
BASH Shell Scripting 265
Perl Scripting 265
Python Scripting 266
Basics of BASH Scripting 268
Conditional Expressions 269
Flow Control Statements 271
The while Loop 272
The for Loop 272
Loop Control 272
The case Statement 272
User Interaction 273
Using Command Substitution 274
Additional Information 274
Summary 274
Key Terms 274
Review Questions 275
Chapter 16 Common Automation Tasks 276
Exploring Scripts that Already Exist on Your System 276
The /etc/cron.* Directories 276
Repositories 279
Creating Your Own Automation Scripts 280
Summary 281
Key Terms 281
Review Questions 281
Chapter 17 Develop an Automation Security Policy 282
Securing crontab and at 282
Securing BASH Scripts 283
Access to Scripts 283
Script Contents 284
Dealing with Data 284
Shell Settings 284
Shell Style 285
Summary 285
Review Questions 285
Part V: Networking 286
Chapter 18 Networking Basics 288
Network Terminology 288
IPv4 Versus IPv6 290
IPv4 Addresses 292
Determining a Network Address from an IP Address and Subnet 293
Private IP Addresses 294
Common Protocol Suites 294
Network Ports 295
Summary 297
Key Terms 297
Review Questions 297
Chapter 19 Network Configuration 298
Ethernet Network Interfaces 298
Displaying Ethernet Port Configurations 299
Changing Ethernet Port Settings 300
Network Configuration Tools 301
The arp Command 302
The route Command 303
The ip Command 304
The hostname Command 305
The host Command 305
The dig Command 306
The netstat Command 307
Persistent Network Configurations 307
The /etc/hostname File (Universal) 307
The /etc/hosts File (Universal) 307
The /[...] File (Universal) 308
The /[...] File (Universal) 308
The /[...] File (Universal) 309
The /etc/sysconfig/network File (Red Hat) 310
The /etc/sysconfig/network-scripts/ifcfg-interface-name Files (Red Hat) 310
The /etc/network/interfaces File (Debian) 311
Network Troubleshooting Commands 311
The ping Command 311
The traceroute Command 312
The netcat Command 313
Access to Wireless Networks 314
The iwconfig Command 314
The iwlist Command 315
Summary 316
Key Terms 316
Review Questions 317
Chapter 20 Network Service Configuration: Essential Services 318
DNS Servers 318
Essential Terms 319
How Name Resolution Works 320
Basic BIND Configuration 322
Zone Files 326
Zone File Basics 326
Zone File Entries in the /[...] File 327
Zone File Syntax 328
Zone Record Types 329
Putting It All Together 333
Slave BIND Servers 335
Testing the DNS Server 336
The dig Command 336
Securing BIND 337
Sending BIND to Jail 337
Split BIND Configuration 340
Transaction Signatures 341
DHCP Server 343
DHCP Configuration Basics 344
Configuring Static Hosts 346
DHCP Log Files 347
Email Servers 347
SMTP Basics 348
Configuring Postfix 349
Managing Local Email...