Ubuntu Linux Unleashed 2021 Edition

Covers 20.04, 20.10, and 21.04 Ubuntu Linux Unleashed 2021 Edition is filled with unique and advanced information for everyone who wants to make the most of the Ubuntu Linux operating system. This new edition has been thoroughly updated by a long-time Ubuntu user and early community leader to reflect the exciting new Ubuntu 20.04 LTS release, with a forthcoming online update mid-2021, at the halfway mark before the next LTS release comes out. Linux writer Matthew Helmke covers all you need to know about Ubuntu 20.04 LTS installation, configuration, productivity, command-line usage, development, systems administration, server operations, networking, virtualization, cloud computing, DevOps, and more—including intermediate-to-advanced techniques you won't find in any other book. Helmke presents up-to-the-minute introductions to Ubuntu's key productivity and web development tools, programming languages, hardware support, and more. You'll find new or improved coverage of the Ubuntu desktop experience, common web servers and software stacks, an introduction to containers like Docker and Kubernetes, as well as a wealth of systems administration information that is stable and valuable over many years. Configure and use the Ubuntu desktop Get started with multimedia and productivity applications Manage Linux services, users, and software packages Administer and run Ubuntu from the command line Automate tasks and use shell scripting Provide secure remote access and configure a secure VPN Manage kernels and modules Administer file, print, email, proxy, LDAP, DNS, and HTTP servers (Apache, Nginx, or alternatives) Work with databases (SQL) and learn about NoSQL alternatives Get started with virtualization and cloud deployment, including information about containers Learn about options for managing large numbers of servers, including in the cloud Learn the basics about popular programming languages including Python, PHP, Perl, and gain an introduction to new alternatives such as Go and Rust

Table of Contents:
Introduction     xxxi PART I: GETTING STARTED Chapter 1  Installing Ubuntu and Post-Installation Configuration     1 Before You Begin the Installation     1     Researching Your Hardware Specifications     2     Installation Options     2     32-Bit Versus 64-Bit Ubuntu     4     Planning Partition Strategies     5     The Boot Loader     5     Installing from DVD or USB Drive     6 Step-by-Step Installation     6     Installing     7     First Update     11 Shutting Down     11 Finding Programs and Files     12 Software Updater     12 The sudo Command     14 Configuring Software Repositories     15 System Settings     17     Detecting and Configuring a Printer     18     Configuring Power Management in Ubuntu     18     Setting the Time and Date     19 Configuring Wireless Networks     20 Troubleshooting Post-Installation Configuration Problems     21 References     22 Chapter 2  Background Information and Resources     23 What Is Linux?     23 Why Use Linux?     25 What Is Ubuntu?     27 Ubuntu for Business     27 Ubuntu in Your Home     28 Getting the Most from Linux and Ubuntu Documentation     28     Linux     29     Ubuntu     30 PART II: DESKTOP UBUNTU Chapter 3  Foundations of the Linux GUI     31 Foundations and the X Server     31     Basic X Concepts     32     Using X     33     Elements of the xorg conf File     34 Starting X     39     Using a Display Manager     39     Changing Window Managers     39 References     40 Chapter 4  Ubuntu Desktop Options     41 Desktop Environment     41 Using GNOME: A Primer     42 KDE and Kubuntu     45 Xfce and Xubuntu     46 LXDE and Lubuntu     47 MATE and Ubuntu MATE     48 Ubuntu Budgie     49 Ubuntu Kylin     50 References     50 Chapter 5  On the Internet     51 Getting Started with Firefox     52 Checking Out Google Chrome and Chromium     53 References     54 Chapter 6  Productivity Applications     55 Introducing LibreOffice     56 Other Useful Productivity Software     58     Working with PDFs     58     Writing Scripts     59     Working with XML and DocBook     59     Working with LaTeX     60     Creating Mind Maps     61 Productivity Applications Written for Microsoft Windows     61 References     61 Chapter 7  Multimedia Applications     63 Sound and Music     63     Sound Cards     64     Sound Formats     65     Listening to Music     65 Graphics Manipulation     66     The GNU Image Manipulation Program     66     Using Scanners in Ubuntu     67     Working with Graphics Formats     67     Capturing Screen Images     69     Other Graphics Manipulation Options     70 Using Digital Cameras with Ubuntu     70     Handheld Digital Cameras     70     Using Shotwell Photo Manager     71 Burning CDs and DVDs in Ubuntu     71     Creating CDs and DVDs with Brasero     71     Creating CDs from the Command Line     72     Creating DVDs from the Command Line     73 Viewing Video     75     Video Formats     75     Viewing Video in Linux     76 Recording and Editing Audio     76 Editing Video     77 References     77 Chapter 8  Games     79 Ubuntu Gaming     79 Installing Proprietary Video Drivers     80 Online Game Sources     81     Steam     81     GOG com     82     Humble     82     itch io     82     LGDB     82     Game Jolt     82 Installing Games from the Ubuntu Repositories     82     Warsow     82     Scorched 3D     83     Frozen Bubble     84     SuperTux     84     Battle for Wesnoth     85     Frets on Fire     85     FlightGear     87     Speed Dreams     87     Games for Kids     88     Commercial Games     88 Playing Windows Games     88 References     89 PART III: SYSTEM ADMINISTRATION Chapter 9  Managing Software         91 Ubuntu Software         91 Using Synaptic for Software Management         92 Staying Up to Date         94 Working on the Command Line         95     Day-to-Day APT Usage         95     Finding Software         98     Using apt-get Instead of apt         99 Compiling Software from Source     100     Compiling from a Tarball     100     Compiling from Source from the Ubuntu Repositories     101 Configuration Management     102     dotdee     102     Ubuntu Core     103 Using the Snappy Package Manager     103 References     104 Chapter 10  Command-Line Beginner's Class     105 What Is the Command Line?     106 Accessing the Command Line     107     Text-Based Console Login     107     Logging Out     108     Logging In and Out from a Remote Computer     108 User Accounts     109 Reading Documentation     111     Using Man Pages     111     Using apropros     112     Using whereis     112 Understanding the Linux File System Hierarchy     112     Essential Commands in /bin and /sbin     114     Configuration Files in /etc     114     User Directories: /home     115     Using the Contents of the /proc Directory to Interact with or Obtain Information from the Kernel     115     Working with Shared Data in the /usr Directory     117     Temporary File Storage in the /tmp Directory     117     Accessing Variable Data Files in the /var Directory     117 Navigating the Linux File System     117     Listing the Contents of a Directory with ls     118     Changing Directories with cd     120     Finding Your Current Directory with pwd     120 Working with Permissions     120     Assigning Permissions     121     Directory Permissions     122     Altering File Permissions with chmod     123     File Permissions with umask     124     File Permissions with chgrp     125     Changing File Permissions with chown     125     Understanding Set User ID, Set Group ID, and Sticky Bit Permissions     125     Setting Permissions with Access Control Lists     127 Working with Files     128     Creating a File with touch     128     Creating a Directory with mkdir     129     Deleting a Directory with rmdir     129     Deleting a File or Directory with rm     130     Moving or Renaming a File with mv     131     Copying a File with cp     131     Displaying the Contents of a File with cat     132     Displaying the Contents of a File with less     132     Using Wildcards and Regular Expressions     133 Working as Root     133     Understanding and Fixing sudo     134     Creating Users     136     Deleting Users     137     Shutting Down the System     137     Rebooting the System     138 Commonly Used Commands and Programs     139 References     139 Chapter 11  Command-Line Master Class, Part 1     141 Why Use the Command Line?     142 Using Basic Commands     143     Printing the Contents of a File with cat     144     Changing Directories with cd     145     Changing File Access Permissions with chmod     147     Copying Files with cp     147     Printing Disk Usage with du     148     Using echo     148     Finding Files by Searching with find     149     Searches for a String in Input with grep     151     Paging Through Output with less     152     Creating Links Between Files with ln     154     Finding Files from an Index with locate     156     Listing Files in the Current Directory with ls     156     Listing System Information with lsblk, lshw, lsmod, lspci, and neofetch     158     Reading Manual Pages with man     159     Making Directories with mkdir     160     Moving Files with mv     161     Renaming Files with rename     161     Deleting Files and Directories with rm     161     Sorting the Contents of a File with sort     162     Printing the Last Lines of a File with tail     163     Printing the Location of a Command with which     164     Downloading Files with wget     164 References     165 Chapter 12  Command-Line Master Class, Part 2     167 Redirecting Output and Input     167 stdin, stdout, stderr, and Redirection     169 Comparing Files     170     Finding Differences in Files with diff     170     Finding Similarities in Files with comm     170 Limiting Resource Use and Job Control     171     Listing Processes with ps     171     Listing Jobs with jobs     173     Running One or More Tasks in the Background     173     Moving Jobs to the Background or Foreground with bg and fg     174     Printing Resource Usage with top     175     Setting Process Priority with nice     177 Combining Commands     178     Pipes     178     Combining Commands with Boolean Operators     180     Running Separate Commands in Sequence     180     Process Substitution     181 Executing Jobs in Parallel     181 Using Environment Variables     182 Using Common Text Editors     185     Working with nano     186     Working with vi     187     Working with emacs     188     Working with sed and awk     189 Working with Compressed Files     191 Using Multiple Terminals with byobu     192 Doing a Polite System Reset Using REISUB     194 Fixing an Ubuntu System That Will Not Boot     195     Checking BIOS     195     Checking GRUB     195     Reinstalling GRUB     195     Using Recovery Mode     196     Reinstalling Ubuntu     196 Tips and Tricks     196     Running the Previous Command     196     Running Any Previous Command     197     Running a Previous Command That Started with Specific Letters     197     Running the Same Thing You Just Ran with a Different First Word     197     Viewing Your History and More     197     Doing Two or More Things     198     Using Shortcuts     198     Confining a Script to a Directory     198     Using Coreutils     199     Reading the Contents of the Kernel Ring Buffer with dmesg     200 References     200 Chapter 13  Managing Users     201 User Accounts     201     The Super User/Root User     202     User IDs and Group IDs     204     File Permissions     204 Managing Groups     205     Group Listing     205     Group Management Tools     206 Managing Users     207     User Management Tools     208     Adding New Users     209     Monitoring User Activity on the System     211 Managing Passwords     212     System Password Policy     212     The Password File     212     Shadow Passwords     214     Managing Password Security for Users     216     Changing Passwords in a Batch     216 Granting System Administrator Privileges to Regular Users     217     Temporarily Changing User Identity with the su Command     217     Granting Root Privileges on Occasion: The sudo Command     219 Disk Quotas     222     Implementing Quotas     222     Manually Configuring Quotas     223 Related Ubuntu Commands     223 References     224 Chapter 14  Automating Tasks and Shell Scripting     225 What Is a Shell?     225 Scheduling Tasks     226     Using at and batch to Schedule Tasks for Later     227     Using cron to Run Jobs Repeatedly     229     Using rtcwake to Wake Your Computer from Sleep Automatically     231 Basic Shell Control     233     The Shell Command Line     233     Shell Pattern-Matching Support     235     Redirecting Input and Output     236     Piping Data     237     Background Processing     237 Writing and Executing a Shell Script     237     Running the New Shell Program     239     Storing Shell Scripts for System-wide Access     240     Interpreting Shell Scripts Through Specific Shells     240     Using Variables in Shell Scripts     242     Assigning a Value to a Variable     242     Accessing Variable Values     243     Positional Parameters     243     A Simple Example of a Positional Parameter     243     Using Positional Parameters to Access and Retrieve Variables from the Command Line     244     Using a Simple Script to Automate Tasks     244     Built-in Variables     246     Special Characters     247     Comparison of Expressions in pdksh and bash     250     Comparing Expressions with tcsh     255     The for Statement     259     The while Statement     261     The until Statement     263     The repeat Statement (tcsh)     263     The select Statement (pdksh)     264     The shift Statement     264     The if Statement     265     The expr Statement     266     The case Statement     267     The break and exit Statements     269     Using Functions in Shell Scripts     269 References     270 Chapter 15  The Boot Process     271 Running Services at Boot     271 Beginning the Boot Loading Process     272 Loading the Linux Kernel     274 Starting and Stopping Services with systemd     275     Controlling Services at Boot with Administrative Tools     278     Troubleshooting Runlevel Problems     278 Boot-Repair     278 References     279 Chapter 16  System-Monitoring Tools     281 Console-Based Monitoring     281     Using the kill Command to Control Processes     283     Using Priority Scheduling and Control     285     Displaying Free and Used Memory with free     286     Disk Space     286     Disk Quotas     287     Checking Log Files     287     Rotating Log Files     289 Graphical Process- and System-Management Tools     292     System Monitor     292     Conky     292     Other Graphical Process- and System-Monitoring Tools     297 KDE Process- and System-Monitoring Tools     298 Enterprise Server Monitoring     298 References     299 Chapter 17  Backing Up     301 Choosing a Backup Strategy     301     Why Data Loss Occurs     302     Assessing Your Backup Needs and Resources     303     Evaluating Backup Strategies     304     Making the Choice     308 Choosing Backup Hardware and Media     308     External Hard Drive     308     Network Storage     308     Tape Drive Backups     309     Cloud Storage     309 Using Backup Software     309     tar: The Most Basic Backup Tool     310     The GNOME File Roller     312     The KDE ark Archiving Tool     312     Déjà Dup     313     Back In Time     314     Unison     315     Amanda     315     Alternative Backup Software     316 Copying Files     316     Copying Files Using tar     317     Compressing, Encrypting, and Sending tar Streams     318     Copying Files Using cp     318     Using rsync     319 Version Control for Configuration Files     320 System Rescue     323     The Ubuntu Rescue Disc     323     Restoring the GRUB2 Boot Loader     323     Saving Files from a Nonbooting Hard Drive     324 References     324 Chapter 18  Networking     325 Laying the Foundation: The localhost Interface     326     Checking for the Availability of the Loopback Interface     326     Configuring the Loopback Interface Manually     327 Checking Connections with ping, traceroute, and mtr     328 Networking with TCP/IP     330     TCP/IP Addressing     331     Using IP Masquerading in Ubuntu     332     Ports     333 IPv6 Basics     334 Network Organization     337     Subnetting     337     Subnet Masks     337     Broadcast, Unicast, and Multicast Addressing     338 Hardware Devices for Networking     338     Network Interface Cards     338     Network Cable     340     Hubs and Switches     342     Routers and Bridges     343     Initializing New Network Hardware     343 Using Network Configuration Tools     345     Command-Line Network Interface Configuration     346     Network Configuration Files     350     Using Graphical Configuration Tools     355 Dynamic Host Configuration Protocol     355     How DHCP Works     356     Activating DHCP at Installation and Boot Time     357     DHCP Software Installation and Configuration     358     Using DHCP to Configure Network Hosts     359     Other Uses for DHCP     361 Wireless Networking     361     Support for Wireless Networking in Ubuntu     361     Choosing from Among Available Wireless Protocols     363 Beyond the Network and onto the Internet     363 Common Configuration Information     364     Configuring Digital Subscriber Line Access     365     Understanding PPP over Ethernet     366     Configuring a PPPoE Connection Manually     366     Configuring Dial-up Internet Access     367     Troubleshooting Connection Problems     368 References     369 Chapter 19  Remote Access with SSH and VNC     371 Setting Up an SSH Server     371 SSH Tools     372     Using scp to Copy Individual Files Between Machines     372     Using sftp to Copy Many Files Between Machines     373     Using ssh-keygen to Enable Key-Based Logins     373 Virtual Network Computing     375 Guacamole     377 References     377 Chapter 20  Securing Your Machines     379 Understanding Computer Attacks     379 Assessing Your Vulnerability     381 Protecting Your Machine     382     Securing a Wireless Network     382     Passwords and Physical Security     383     Configuring and Using Tripwire     384     Securing Devices     385 Viruses     385 Configuring Your Firewall     386 AppArmor     388 Forming a Disaster Recovery Plan     390 References     391 Chapter 21  Performance Tuning     393 Storage Disk     394     Linux File Systems     394     The hdparm Command     395     File System Tuning     396     The tune2fs Command     396     The e2fsck Command     397     The badblocks Command     397     Disabling File Access Time     397 Kernel     398 Tuned     399 Chapter 22  Kernel and Module Management     401 The Linux Kernel     402     The Linux Source Tree     403     Types of Kernels     405 Managing Modules     406 When to Recompile     408 Kernel Versions     409 Obtaining the Kernel Sources     409 Patching the Kernel     410 Compiling the Kernel     412     Using xconfig to Configure the Kernel     414     Creating an Initial RAM Disk Image     418 When Something Goes Wrong     418     Errors During Compile     418     Runtime Errors, Boot Loader Problems, and Kernel Oops     419 References     419 PART IV: UBUNTU AS A SERVER Chapter 23  Sharing Files and Printers     421 Using Network File System     422     Installing and Starting or Stopping NFS     422     NFS Server Configuration     422     NFS Client Configuration     423 Putting Samba to Work     424     Manually Configuring Samba with /etc/samba/smb conf     426     Testing Samba with the testparm Command     429     Starting, Stopping, and Restarting the smbd Daemon     429     Mounting Samba Shares     430 Network and Remote Printing with Ubuntu     431     Creating Network Printers     431     Using the CUPS GUI     433     Avoiding Printer Support Problems     434 References     435 Chapter 24  Common Web Server Stacks     437 LAMP     437 LEMP     439 MEAN     440 References     441 Chapter 25  Apache Web Server Management     443 About the Apache Web Server     443 Installing the Apache Server     444     Starting and Stopping Apache     444 Runtime Server Configuration Settings     446     Runtime Configuration Directives     446     Editing apache2 conf     447     Apache Multiprocessing Modules     449     Using htaccess Configuration Files     450 File System Authentication and Access Control     452     Restricting Access with Require     452     Authentication     453     Final Words on Access Control     455 Apache Modules     455     mod_access     456     mod_alias     456     mod_asis     456     mod_auth     457     mod_auth_anon     457     mod_auth_dbm     457     mod_auth_digest     457     mod_autoindex     458     mod_cgi     458     mod_dir and mod_env     458     mod_expires     458     mod_headers     458     mod_include     459     mod_info and mod_log_config     459     mod_mime and mod_mime_magic     459     mod_negotiation     459     mod_rewrite     459     mod_setenvif     460     mod_speling     460     mod_status     460     mod_ssl     460     mod_unique_id     460     mod_userdir     460     mod_usertrack     460     mod_vhost_alias     460 Virtual Hosting     461     Address-Based Virtual Hosts     461     Name-Based Virtual Hosts     461 Logging     463 HTTPS     464 References     466 Chapter 26  Nginx Web Server Management     467 About the Nginx Web Server     467 Installing the Nginx Server     469     Installing from the Ubuntu Repositories     469     Building the Source Yourself     469 Configuring the Nginx Server     470 Virtual Hosting     473 Setting Up PHP     474 Adding and Configuring Modules     475 HTTPS     476 Reference     477 Chapter 27  Other HTTP Servers     479 Lighttpd     479 Yaws     480 Cherokee     480 Jetty     481 thttpd     481 Apache Tomcat     482 WildFly     482 Caddy     482 References     482 Chapter 28  Administering Relational Database Services     483 A Brief Review of Database Basics     484     How Relational Databases Work     486     Understanding SQL Basics     487     Creating Tables     488     Inserting Data into Tables     489     Retrieving Data from a Database     490 Choosing a Database: MySQL Versus PostgreSQL     492     Speed     492     Data Locking     492     ACID Compliance in Transaction Processing to Protect Data Integrity     493     SQL Subqueries     494     Procedural Languages and Triggers     494 Configuring MySQL     494     Setting a Password for the MySQL Root User     495     Creating a Database in MySQL     496 Configuring PostgreSQL     498     Initializing the Data Directory in PostgreSQL     498     Creating a Database in PostgreSQL     499     Creating Database Users in PostgreSQL     499     Deleting Database Users in PostgreSQL     500     Granting and Revoking Privileges in PostgreSQL     500 Database Clients     501     SSH Access to a Database     501     Local GUI Client Access to a Database     503     Web Access to a Database     503     The MySQL Command-Line Client     504     The PostgreSQL Command-Line Client     505     Graphical Clients     506 References     507 Chapter 29  NoSQL Databases     509 Key/Value Stores     512     Berkeley DB     512     Cassandra     513     etcd     513     Memcached and MemcacheDB     513     Redis     514     Riak     514     Scylla     514 Document Stores     514     CouchDB     515     MongoDB     516     BaseX     517 Wide Column Stores     517     BigTable     517     HBase     518 Graph Stores     518     Neo4j     518     OrientDB     519     HyperGraphDB     519     FlockDB     519 References     519 Chapter 30  Virtualization on Ubuntu     521 KVM     523 VirtualBox     527 VMware     528 Xen     528 References     529 Chapter 31  Containers and Ubuntu     531 LXC and LXD     532 Docker     533 Kubernetes     534 References     534 Chapter 32  Ubuntu and Cloud Computing     535 Why a Cloud?     536     Software as a Service (SaaS)     537     Platform as a Service (PaaS)     537     Infrastructure as a Service (IaaS)     537     Metal as a Service (MaaS)     537     Things to Consider Before You Make Any Decisions     538 Ubuntu on the Public Cloud     538     OpenStack     538     Amazon Web Services     539     Google Cloud     539     Microsoft Azure     539     Hybrid Clouds     539 Canonical-Specific Cloud Offerings     540     Juju     540     Mojo: Continuous Delivery for Juju     541     Landscape     541 References     541 Chapter 33  Managing Sets of Servers     543 Puppet     543 Chef     544 Ansible     544 SaltStack     544 CFEngine     545 Juju     545 Landscape     545 References     545 Chapter 34  Handling Email     547 How Email Is Sent and Received     547     The Mail Transport Agent     548     Choosing an MTA     550     The Mail Delivery Agent     550     The Mail User Agent     551 Basic Postfix Configuration and Operation     552     Configuring Masquerading     554     Using Smart Hosts     554     Setting Message Delivery Intervals     555     Mail Relaying     555     Forwarding Email with Aliases     556 Using Fetchmail to Retrieve Mail     557     Installing Fetchmail     557     Configuring Fetchmail     557 Choosing a Mail Delivery Agent     560     Procmail     561     Spamassassin     561     Squirrelmail     561     Virus Scanners     562     Autoresponders     562 References     562 Chapter 35  Proxying, Reverse Proxying, and Virtual Private Networks (VPNs)     563 What Is a Proxy Server?     563 Installing Squid     564 Configuring Clients     564 Access Control Lists     565 Specifying Client IP Addresses     569 Sample Configurations     570 Virtual Private Networks (VPNs)     572     Setting Up a VPN Client     573     Setting Up a VPN Server     575 References     577 Chapter 36  Lightweight Directory Access Protocol (LDAP)     579 Configuring the Server     580     Creating Your Schema     580     Populating Your Directory     582 Configuring Clients     584 LDAP Administration     584 References     585 Chapter 37  Name Serving with the Domain Name System (DNS)     587 Understanding Domain Names     588     DNS Servers     589     DNS Records     590 Setting Up a DNS Server with BIND     593 References     595 PART V: PROGRAMMING LINUX Chapter 38  Using Programming Tools     597 Programming in C with Linux     598 Using the C Programming Project Management Tools Provided with Ubuntu     599     Building Programs with make     599     Using the autoconf Utility to Configure Code     601     Debugging Tools     602 Using the GNU C Compiler     603 Programming in Java with Linux     604 Graphical Development Tools     605     IDEs and SDKs     605     Using the KDevelop Client     606     The Glade Client for Developing in GNOME     607 Beginning Mobile Development for Android     607     Hardware     608     Linux Kernel     608     Libraries     608     Android Runtime     608     Application Framework     608     Applications     609     Installing Android Studio     609     Creating Your First Android Application     609 Version Control Systems     609     Managing Software Projects with Git     610     Managing Software Projects with Bazaar     611     Managing Software Projects with Subversion     612 Continuous Integration and Continuous Delivery and DevOps Tools     613     CI/CD Tools     614     Chaos Engineering     614 Canonical-created Tools     614     Launchpad     614     Ubuntu Make     615     Creating Snap Packages     615     Bikeshed and Other Tools     616 References     618 Chapter 39  Using Popular Programming Languages     621 Ada     622 Clojure     622 COBOL     623 D     624 Dart     624 Elixir     625 Elm     625 Erlang     625 Forth     626 Fortran     626 Go     626 Groovy     627 Haskell     627 Java     627 JavaScript     628 Kotlin     628 Lisp     629 Lua     629 Mono     629 OCaml     630 Perl     630 PHP     631 Python     631 Raku     631 Ruby     631 Rust     632 Scala     632 Scratch     632 Vala     633 References     633 Chapter 40  Helping with Ubuntu Development     635 Introduction to Ubuntu Development     636 Setting Up Your Development System     637     Install Basic Packages and Configure     637     Creating a Launchpad Account     638     Setting Up Your Environment to Work with Launchpad     638 Fixing Bugs and Packaging     640 References     643 Chapter 41  Helping with Ubuntu Testing and QA     645 Community Teams     645     Ubuntu Testing Team     646     Ubuntu QA Team     646 Bug Squad     647 References     647 Index     649 PART VI: BONUS ONLINE-ONLY CHAPTERS Chapter 42  Using Perl (Online)     Web:1 Using Perl with Linux     Web:1     Perl Versions      Web:2     A Simple Perl Program     Web:2 Perl Variables and Data Structures     Web:4     Perl Variable Types     Web:4     Special Variables     Web:5 Perl Operators     Web:6     Comparison Operators     Web:6     Compound Operators     Web:7     Arithmetic Operators     Web:7     Other Operators     Web:8     Special String Constants     Web:8 Conditional Statements: if/else and unless     Web:9     If     Web:9     unless     Web:9 Looping     Web:10     for     Web:10     foreach     Web:10     while     Web:11     until     Web:11     last and next     Web:12     do while and do until     Web:12 Regular Expressions     Web:12 Access to the Shell     Web:13 Modules and CPAN     Web:14 Code Examples     Web:15     Sending Mail     Web:15     Purging Logs     Web:17     Posting to Usenet     Web:18     One-Liners     Web:19     Command-Line Processing     Web:19 References     Web:20 Chapter 43  Using Python (Online)     Web:21 Python on Linux     Web:22 The Basics of Python     Web:23     Numbers     Web:23     More on Strings     Web:24     Lists     Web:27     Dictionaries     Web:30     Conditionals and Looping     Web:30 Functions     Web:33 Object Orientation     Web:34     Class and Object Variables     Web:34     Constructors and Destructors     Web:35     Class Inheritance     Web:36 The Standard Library and the Python Package Index     Web:38 References     Web:38 Chapter 44  Using PHP (Online)     Web:39 Introduction to PHP     Web:39     Entering and Exiting PHP Mode     Web:40     Variables     Web:40     Arrays     Web:42     Constants     Web:43     References     Web:44     Comments     Web:44     Escape Sequences     Web:45     Variable Substitution     Web:46     Operators     Web:46     Conditional Statements     Web:48     Special Operators     Web:50     Switching     Web:51     Loops     Web:52     Including Other Files     Web:54 Basic Functions     Web:55     Strings     Web:55     Arrays     Web:58     Files     Web:60     Miscellaneous     Web:63 Handling HTML Forms     Web:66 Databases     Web:67 References     Web:69