Title Page Copyright and Credits Mastering Linux Shell Scripting Second Edition Packt Upsell Why subscribe? PacktPub.com Contributors About the authors 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 The What and Why of Scripting with Bash Technical requirements Types of Linux shells What is bash scripting? The bash command hierarchy Command type Command PATH Preparing text editors for scripting Configuring vim Configuring nano Configuring gedit Creating and executing scripts Hello World! Executing the script Checking the exit status Ensuring a unique name Hello Dolly! Running the script with arguments The importance of correct quotes Printing the script name Declaring variables User-defined variables Environment variables Variable scope Command substitution Debugging your scripts Summary Questions Further reading Creating Interactive Scripts Technical requirements Using echo with options Basic script using read Script comments Enhancing scripts with read prompts Limiting the number of entered characters Controlling the visibility of the entered text Passing options Passing parameters with options Read options values Try to be standard Enhancing learning with simple scripts Backing-up with scripts Connecting to a server Version 1 – ping Version 2 – SSH Version 3 – MySQL/MariaDB Reading files Summary Questions Further reading Conditions Attached Technical requirements Simple decision paths using command-line lists Verifying user input with lists Using the test shell built-in Testing strings Testing integers Testing file types Creating conditional statements using if Extending if with else Test command with the if command Checking strings Checking files and directories Checking numbers Combining tests More conditions with elif Creating the backup2.sh using elif Using case statements Recipe – building a frontend with grep Summary Questions Further reading Creating Code Snippets Technical requirements Abbreviations Using code snippets Bringing color to the Terminal Creating snippets using VS Code Summary Questions Further reading Alternative Syntax Technical requirement Recapping the test command Testing files Adding logic Square brackets as not seen before Providing parameter defaults Variables Special parameters Setting defaults When in doubt – quote! Advanced tests using [[ White space Other advanced features Pattern matching Regular expressions Regular expression script Arithmetic operations using (( Simple math Parameter manipulation Standard arithmetic tests Summary Questions Further reading Iterating with Loops Technical requirement for loops Advanced for loops The IFS Counting directories and files C-style for loops  Nested loops Redirecting loop output Controlling the loop while loops and until loops Reading input from files Creating operator menus Summary Questions Further reading Creating Building Blocks with Functions Technical requirements Introducing functions Passing parameters to functions Passing arrays Variable scope Returning values from functions Recursive functions Using functions in menus Summary Questions Further reading Introducing the Stream Editor Technical requirements Using grep to display text Displaying received data on an interface Displaying user account data Listing the number of CPUs in a system Parsing CSV files The CSV file Isolating catalog entries Understanding the basics of sed The substitute command Global replacement Limiting substitution Editing the file Other sed commands The delete command The insert and append commands The change command The transform command Multiple sed commands Summary Questions Further reading Automating Apache Virtual Hosts Technical requirements Apache name-based Virtual Hosts Creating the virtual host template First steps Isolating lines sed script files Automating virtual host creation Prompting for data during site creation Summary Questions Further reading AWK Fundamentals Technical requirements The history behind AWK Displaying and filtering content from files AWK variables User-defined variables Conditional statements The if command while loops for loops Formatting output Further filtering to display users by UID AWK control files Built-in functions Summary Questions Further reading Regular Expressions Technical requirements Regular expression engines Defining BRE patterns Anchor characters The dot character The character class Ranges of characters Special character classes The asterisk Defining ERE patterns The question mark The plus sign Curly braces The pipe character Expression grouping Using grep Summary Questions Further reading Summarizing Logs with AWK Technical requirements The HTTPD log file format Displaying data from web logs Selecting entries by date Summarizing 404 errors Summarizing HTTP access codes Resources hits Identify image hotlinking Displaying the highest ranking IP address Displaying the browser data Working with email logs Summary Questions Further reading A Better lastlog with AWK Technical requirements Using AWK ranges to exclude data The lastlog command Horizontally filtering rows with AWK Counting matched rows Conditions based on the number of fields Manipulating the AWK record separator to report on XML data Apache Virtual Hosts XML catalog Summary Questions Further reading Using Python as a Bash Scripting Alternative Technical requirements What is Python? Saying Hello World the Python way Pythonic arguments Supplying arguments Counting arguments Significant whitespace Reading user input Using Python to write to files String manipulation Summary Questions Further reading Assessments Chapter 1 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 Other Books You May Enjoy Leave a review - let other readers know what you think