Linux Bible

Christopher Negus has been teaching and writing about Linux and UNIX for more than 25 years. He is an instructor and principal technical writer for Red Hat, Inc., and the author of dozens of Linux and UNIX books, including Red Hat Linux Bible (all editions), CentOS Bible, Fedora Bible, Ubuntu Linux Toolbox, Linux Troubleshooting Bible, Linux Toys, and Linux Toys II.

• Acknowledgments xiIntroduction xxxvPart I: Getting Started 1Chapter 1: Starting with Linux 3Understanding What Linux Is 4Understanding How Linux Differs from Other Operating Systems 6Exploring Linux History 7Free-flowing UNIX culture at Bell Labs 7Commercial UNIX 9GNU transitions UNIX to freedom 11BSD loses some steam 12Linus builds the missing piece 13OSI open source definition 14Understanding How Linux Distributions Emerged 16Choosing a Red Hat distribution 16Choosing Ubuntu or another Debian distribution 19Finding Professional Opportunities with Linux Today 19Understanding how companies make money with Linux 20Becoming Red Hat certified 21Summary 25Chapter 2: Creating the Perfect Linux Desktop 27Understanding Linux Desktop Technology 28Starting with the Fedora GNOME Desktop Live image 30Using the GNOME 3 Desktop 31After the computer boots up 31Setting up the GNOME 3 desktop 38Extending the GNOME 3 desktop 39Starting with desktop applications 41Stopping the GNOME 3 desktop 46Using the GNOME 2 Desktop 46Using the Metacity window manager 48Changing GNOME’s appearance 49Using the GNOME panels 50Adding 3D effects with AIGLX 54Summary 57Exercises 57Part II: Becoming a Linux Power User 59Chapter 3: Using the Shell 61About Shells and Terminal Windows 62Using the shell prompt 63Using a Terminal window 63Using virtual consoles 65Choosing Your Shell 65Running Commands 66Understanding command syntax 67Locating commands 70Recalling Commands Using Command History 72Command-line editing 73Command-line completion 75Command-line recall 76Connecting and Expanding Commands 78Piping between commands 78Sequential commands 79Background commands 79Expanding commands 80Expanding arithmetic expressions 80Expanding variables 80Using Shell Variables 81Creating and using aliases 81Exiting the shell 83Creating Your Shell Environment 84Configuring your shell 84Setting your prompt 85Adding environment variables 87Getting Information about Commands 88Summary 90Exercises 90Chapter 4: Moving Around the Filesystem 93Using Basic Filesystem Commands 96Using Metacharacters and Operators 98Using file-matching metacharacters 98Using file-redirection metacharacters 99Using brace expansion characters 101Listing Files and Directories 101Understanding File Permissions and Ownership 105Changing permissions with chmod (numbers) 106Changing permissions with chmod (letters) 107Setting default file permission with umask 108Changing file ownership 109Moving, Copying, and Removing Files 109Summary 111Exercises 111Chapter 5: Working with Text Files 113Editing Files with vim and vi 113Starting with vi 115Skipping around in the file 119Searching for text 119Using ex mode 120Learning more about vi and vim 120Finding Files 120Using locate to find files by name 121Searching for files with find 122Searching in files with grep 128Summary 129Exercises 129Chapter 6: Managing Running Processes 131Understanding Processes 131Listing Processes 132Listing processes with ps 132Listing and changing processes with top 134Listing processes with System Monitor 136Managing Background and Foreground Processes 137Starting background processes 138Using foreground and background commands 139Killing and Renicing Processes140Killing processes with kill and killall 140Setting processor priority with nice and renice 142Limiting Processes with cgroups 143Summary 144Exercises 145Chapter 7: Writing Simple Shell Scripts 147Understanding Shell Scripts 147Executing and debugging shell scripts 148Understanding shell variables 149Performing arithmetic in shell scripts 152Using programming constructs in shell scripts 153Trying some useful text manipulation programs 159Using simple shell scripts 161Summary 163Exercises 163Part III: Becoming a Linux System Administrator 165Chapter 8: Learning System Administration 167Understanding System Administration 167Using Graphical Administration Tools 169Using the root User Account 174Exploring Administrative Commands, Configuration Files, and Log Files 178Administrative commands 178Administrative configuration files 179Using Other Administrative Accounts 185Checking and Configuring Hardware 186Checking your hardware 187Managing removable hardware 189Working with loadable modules 191Summary 193Exercises 193Chapter 9: Installing Linux 195Choosing a Computer 196Installing Fedora from Live Media 198Installing Red Hat Enterprise Linux from Installation Media 201Understanding Cloud-Based Installations 204Installing Linux in the Enterprise 205Exploring Common Installation Topics 207Upgrading or installing from scratch 207Dual booting 208Installing Linux to run virtually 209Using installation boot options 210Using specialized storage 213Partitioning hard drives 214Using the GRUB boot loader 217Summary 219Exercises 219Chapter 10: Getting and Managing Software 221Managing Software on the Desktop 221Going Beyond the Software Window 223Understanding Linux RPM and DEB Software Packaging 224Understanding DEB packaging 225Understanding RPM packaging 226Managing RPM Packages with YUM 229Transitioning from yum to dnf 229Understanding how yum works 229Using YUM with third-party software repositories 233Managing software with the yum command 233Installing, Querying, and Verifying Software with the rpm Command 241Installing and removing packages with rpm 241Querying rpm information 242Verifying RPM packages 244Managing Software in the Enterprise 245Summary 246Exercises 247Chapter 11: Managing User Accounts 249Creating User Accounts 249Adding users with useradd 252Setting user defaults 255Modifying users with usermod 257Deleting users with userdel 258Understanding Group Accounts 259Using group accounts 259Creating group accounts 260Managing Users in the Enterprise 261Setting permissions with Access Control Lists 262Centralizing User Accounts 269Summary 270Exercises 270Chapter 12: Managing Disks and Filesystems 273Understanding Disk Storage 273Partitioning Hard Disks 275Understanding partition tables 275Viewing disk partitions 276Creating a single-partition disk 277Creating a multiple-partition disk 281Using Logical Volume Manager Partitions 285Checking an existing LVM 286Creating LVM logical volumes 289Growing LVM logical volumes 290Mounting Filesystems 291Supported filesystems 291Enabling swap areas 293Disabling swap area 294Using the fstab file to define mountable file systems 295Using the mount command to mount file systems 297Mounting a disk image in loopback 298Using the umount command 299Using the mkfs Command to Create a Filesystem 300Managing Storage with Cockpit 301Summary 303Exercises 303Part IV: Becoming a Linux Server Administrator 305Chapter 13: Understanding Server Administration 307Starting with Server Administration 308Step 1: Install the server 308Step 2: Configure the server 310Step 3: Start the server 311Step 4: Secure the server 312Step 5: Monitor the server 314Checking and Setting Servers 316Managing Remote Access with the Secure Shell Service 316Starting the openssh-server service 317Using SSH client tools 318Using key-based (passwordless) authentication 324Configuring System Logging 326Enabling system logging with rsyslog 326Watching logs with logwatch 331Checking System Resources with sar 332Checking System Space 334Displaying system space with df 334Checking disk usage with du 334Finding disk consumption with find 335Managing Servers in the Enterprise 336Summary 336Exercises 337Chapter 14: Administering Networking 339Configuring Networking for Desktops 340Checking your network interfaces 342Configuring network interfaces 349Configuring a network proxy connection 352Configuring Networking from the Command Line 353Configure networking with nmtui 354Editing a NetworkManager TUI connection 354Understanding networking configuration files 355Setting alias network interfaces 360Setting up Ethernet channel bonding 361Setting custom routes 363Configuring Networking in the Enterprise 364Configuring Linux as a router 364Configuring Linux as a DHCP server 365Configuring Linux as a DNS server 365Configuring Linux as a proxy server 366Summary 366Exercises 367Chapter 15: Starting and Stopping Services 369Understanding the Initialization Daemon (init or systemd) 370Understanding the classic init daemons 371Understanding systemd initialization 377Checking the Status of Services 384Checking services for SysVinit systems 385Stopping and Starting Services 387Stopping and starting SysVinit services 387Enabling Persistent Services 391Configuring persistent services for SysVinit 391Configuring a Default Runlevel or Target Unit 394Configuring the SysVinit default runlevel 394Adding New or Customized Services 396Adding new services to SysVinit 396Adding new services to systemd 399Summary 401Exercises 401Chapter 16: Configuring a Print Server 403Common UNIX Printing System 403Setting Up Printers 405Adding a printer automatically 405Using web-based CUPS administration 406Using the Print Settings window 409Working with CUPS Printing 415Configuring the CUPS server (cupsdconf) 415Starting the CUPS server 417Configuring CUPS printer options manually 417Using Printing Commands 418Printing with lp 419Listing status with lpstat -t 419Removing print jobs with lprm 419Configuring Print Servers 420Configuring a shared CUPS printer 420Configuring a shared Samba printer 422Summary 424Exercises 424Chapter 17: Configuring a Web Server 427Understanding the Apache Web Server 427Getting and Installing Your Web Server 428Understanding the httpd package 428Installing Apache 431Starting Apache 432Securing Apache 433Understanding the Apache configuration files 435Adding a virtual host to Apache 440Allowing users to publish their own web content 442Securing your web traffic with SSL/TLS 443Troubleshooting Your Web Server 449Checking for configuration errors 449Accessing forbidden and server internal errors 451Summary 453Exercises 453Chapter 18: Configuring an FTP Server 455Understanding FTP 455Installing the vsftpd FTP Server 457Starting the vsftpd Service 458Securing Your FTP Server 461Opening up your firewall for FTP 461Configuring SELinux for your FTP server 463Relating Linux file permissions to vsftpd 465Configuring Your FTP Server 465Setting up user access 465Allowing uploading 467Setting up vsftpd for the Internet 468Using FTP Clients to Connect to Your Server 469Accessing an FTP server from Firefox 470Accessing an FTP server with the lftp command 470Using the gFTP client 472Summary 473Exercises 473Chapter 19: Configuring a Windows File Sharing (Samba) Server 475Understanding Samba 475Installing Samba 476Starting and Stopping Samba 478Starting the Samba (smb) service 478Starting the NetBIOS (nmbd) name server 480Stopping the Samba (smb) and NetBIOS (nmb) services 481Securing Samba 482Configuring firewalls for Samba 482Configuring SELinux for Samba 484Configuring Samba host/user permissions 486Configuring Samba 486Configuring the [global] section 486Configuring the [homes] section487Configuring the [printers] section 489Accessing Samba Shares 493Accessing Samba shares in Linux 493Accessing Samba shares in Windows 496Using Samba in the Enterprise 497Summary 497Exercises 498Chapter 20: Configuring an NFS File Server 499Installing an NFS Server 502Starting the NFS service 502Sharing NFS Filesystems 503Configuring the /etc/exports file 504Exporting the shared filesystems 507Securing Your NFS Server 508Opening up your firewall for NFS 508Allowing NFS access in TCP wrappers 510Configuring SELinux for your NFS server 511Using NFS Filesystems 512Viewing NFS shares 512Manually mounting an NFS filesystem 512Mounting an NFS filesystem at boot time 513Using autofs to mount NFS filesystems on demand 517Unmounting NFS filesystems 520Summary 521Exercises 521Chapter 21: Troubleshooting Linux 523Boot-Up Troubleshooting 523Understanding Startup Methods 524Starting from the firmware (BIOS or UEFI) 526Troubleshooting the GRUB boot loader 528GRUB 2 Boot loader 530Starting the kernel 532Troubleshooting Software Packages 542Fixing RPM databases and cache 545Troubleshooting Networking 547Troubleshooting outgoing connections 547Troubleshooting incoming connections 550Troubleshooting Memory 553Uncovering memory issues 554Troubleshooting in Rescue Mode 559Summary 561Exercises 561Part V: Learning Linux Security Techniques 563Chapter 22: Understanding Basic Linux Security 565Implementing Physical Security 565Implementing disaster recovery 566Securing user accounts 566Securing passwords 570Securing the filesystem 576Managing software and services 579Advanced implementation 580Monitoring Your Systems 580Monitoring log files 581Monitoring user accounts 584Monitoring the filesystem 587Auditing and Reviewing Linux 595Conducting compliance reviews 595Conducting security reviews 596Summary 596Exercises 597Chapter 23: Understanding Advanced Linux Security 599Implementing Linux Security with Cryptography 599Understanding hashing 600Understanding encryption/decryption 602Implementing Linux cryptography 610Implementing Linux Security with PAM 618Understanding the PAM authentication process 619Administering PAM on your Linux system 622Obtaining more information on PAM 633Summary 633Exercises 633Chapter 24: Enhancing Linux Security with SELinux 635Understanding SELinux Benefits 635Understanding How SELinux Works 637Understanding Type Enforcement 637Understanding Multi-Level Security 638Implementing SELinux security models 639Configuring SELinux 645Setting the SELinux mode 645Setting the SELinux policy type 647Managing SELinux security contexts 648Managing SELinux policy rule packages 651Managing SELinux via Booleans 653Monitoring and Troubleshooting SELinux 654Understanding SELinux logging 654Troubleshooting SELinux logging 656Troubleshooting common SELinux problems 657Putting It All Together 659Obtaining More Information on SELinux 659Summary 660Exercises 660Chapter 25: Securing Linux on a Network 663Auditing Network Services 663Evaluating access to network services with nmap 665Using nmap to audit your network services advertisements 668Working with Firewalls 672Understanding firewalls 673Implementing firewalls 674Summary 688Exercises 688Part VI: Engaging with Cloud Computing 691Chapter 26: Shifting to Clouds and Containers 693Understanding Linux Containers 694Namespaces 695Container registries 695Base images and layers 696Starting with Linux Containers 697Pulling and running containers 697Starting and stopping containers 701Building a container image 702Tagging and pushing an image to a registry 705Using containers in the enterprise 706Summary 706Exercises 707Chapter 27: Using Linux for Cloud Computing 709Overview of Linux and Cloud Computing 710Trying Basic Cloud Technology 713Setting Up a Small Cloud 714Configuring hypervisors 715Configuring storage 718Creating virtual machines 720Managing virtual machines 724Migrating virtual machines 725Summary 727Exercises 727Chapter 28: Deploying Linux to the Cloud 729Getting Linux to Run in a Cloud 729Creating Linux Images for Clouds 731Configuring and running a cloud-init cloud instance 731Investigating the cloud instance 733Cloning the cloud instance 734Using cloud-init in enterprise computing 738Using OpenStack to Deploy Cloud Images 739Starting from the OpenStack Dashboard 739Using Amazon EC2 to Deploy Cloud Images 744Summary 746Exercises 746Chapter 29: Automating Apps and Infrastructure with Ansible 749Understanding Ansible 750Exploring Ansible Components 751Inventories 751Playbooks 752Stepping Through an Ansible Deployment 753Installing Ansible 756Running Ad-Hoc Ansible Commands 760Automating Tasks with Ansible Tower Automation Framework 762Summary 763Exercises 763Chapter 30: Deploying Applications as Containers with Kubernetes 765Understanding Kubernetes 766Kubernetes masters 766Kubernetes workers 767Kubernetes applications 767Kubernetes interfaces 768Trying Kubernetes 768Getting Kubernetes 769Running the Kubernetes Basics tutorial 771Enterprise-Quality Kubernetes with OpenShift 782Summary 783Exercises 783Part VII: Appendixes 785Appendix A: Media 787Appendix B: Exercise Answers 797Index 863