Title Page Copyright and Credits Learn Linux Shell Scripting – Fundamentals of Bash 4.4 About Packt Why subscribe? PacktPub.com Contributors About the author About the reviewer Packt is searching for authors like you Preface Who this book is for What this book covers To get the most out of this book Download the example code files Download the color images Conventions used Get in touch Reviews Disclaimer Introduction What is Linux? What is Bash? Summary Setting Up Your Local Environment Technical requirements Choosing between a virtual machine and a physical installation Setting up VirtualBox Creating an Ubuntu virtual machine Creating the virtual machine in VirtualBox Installing Ubuntu on the virtual machine Accessing the virtual machine via SSH Summary Questions Further reading Choosing the Right Tools Technical requirements Using graphical editors for shell scripting Atom Atom installation and configuration Notepad++ Using command-line editors Vim Vim summary .vimrc Vim cheat sheet nano Combining graphical editors with command-line editors when writing shell scripts Summary Questions Further reading The Linux Filesystem Technical requirements The Linux filesystem explained What is a filesystem? What makes the Linux filesystem unique? Structure of the Linux filesystem Tree structure Overview of top-level directories What about multiple partitions? /bin/, /sbin/, and /usr/ /etc/ /opt/, /tmp/, and /var/ Everything is a file Different types of files Summary Questions Further reading Understanding the Linux Permissions Scheme Technical requirements Read, write, and execute RWX Users, groups, and others Manipulating file permissions and ownership chmod, umask sudo, chown, and chgrp sudo chown, chgrp Working with multiple users Advanced permissions File attributes Special file permissions Access Control Lists (ACLs) Summary Questions Further reading File Manipulation Technical requirements Common file operations Copying Removing Renaming, moving, and linking Archiving Finding files locate find Summary Questions Further reading Hello World! Technical requirements First steps The shebang Running scripts Readability Comments Script header Verbosity Verbosity in comments Verbosity of commands Verbosity of command output Keep It Simple, Stupid (KISS) Summary Questions Further reading Variables and User Input Technical requirements What is a variable? Why do we need variables? Variables or constants? Variable naming Dealing with user input Basic input Parameters and arguments Interactive versus non-interactive scripts Combining positional arguments and read Summary Questions Further reading Error Checking and Handling Technical requirements Error checking Exit status Functional checks Test shorthand Variable refresher Bash debugging Error handling if-then-exit if-then-else Shorthand syntax Error prevention Checking arguments Managing absolute and relative paths Dealing with y/n Summary Questions Further reading Regular Expressions Technical requirements Introducing regular expressions What is a regular expression? grep Greediness Character matching Line anchors Character classes Globbing What is globbing? Similarities with regular expressions More globbing Advanced globbing Disabling globbing, and other options Using regular expressions with egrep and sed Advanced grep Introducing egrep sed, the stream editor Stream editing In-place editing Line manipulation Final remarks Summary Questions Further reading Conditional Testing and Scripting Loops Technical requirements Advanced if-then-else A recap on if-then-else  Using regular expressions in tests The elif condition Nesting Getting help The while loop The until loop Creating an interactive while loop The for loop Globbing and the for loop Loop control Breaking the loop The continue keyword Loop control and nesting Summary Questions Further reading Using Pipes and Redirection in Scripts Technical requirements Input/output redirection File descriptors Redirecting output stdout stderr Redirect all output Special output redirection /dev/null /dev/zero Input redirection Generating a password Advanced redirecting Redirecting redirections Command substitution Process substitution Pipes Binding stdout to stdin Practical examples Yet another password generator Setting passwords in a script tee Here documents Heredocs and variables Using heredocs for script input Here strings Summary Questions Further reading Functions Technical requirements Functions explained Hello world! More complexity Variable scopes Practical examples Error handling Augmenting functions with parameters Colorful Returning values Function libraries Source More practical examples Current working directory Type checking Yes-no check Summary Questions Further reading Scheduling and Logging Technical requirements Scheduling with at and cron at Time syntax The at queue at output cron crontab Syntax for the crontab Logging script results Crontab environment variables PATH SHELL MAILTO Logging with redirection Final logging considerations A note on verbosity Summary Questions Further reading Parsing Bash Script Arguments with getopts Technical requirements Positional parameters versus flags Using flags on the command line The getopts shell builtin The getopts syntax Multiple flags Flags with arguments Combining flags with positional arguments Summary Questions Further reading Bash Parameter Substitution and Expansion Technical requirements Parameter expansion Parameter substitutions – recap Default values Input checking Parameter length Variable manipulation Pattern substitution Pattern removal Case modification Substring expansion Summary Questions Further reading Tips and Tricks with Cheat Sheet Technical requirements General tips and tricks Arrays The history command Creating your own aliases Command-line shortcuts Fun with exclamation marks Running commands from the history Keyboard shortcuts Copying and pasting from the terminal Reverse search Cheat sheet for interactive commands Navigation cd ls pwd File manipulation cat less touch mkdir cp rm mv ln head tail Permissions and ownership chmod umask chown chgrp sudo su useradd groupadd usermod Summary Final words Assessments Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Other Books You May Enjoy Leave a review - let other readers know what you think
Learn Linux Shell Scripting - Fundamentals of Bash 4.4
Published by
Packt Publishing, 2018