Linux Shell Scripting: Automating Command Line Tasks [Video]

More Information
Learn
  • Choose the right automation technique
  • Write user-friendly scripts
  • Debug the system, not scripts
  • Write complex scripts with branches and loops
  • Delve into Linux system calls
  • Profile scripts and increase performance
  • Set up and secure a cloud MySQL database for your web app
  • Add logging to your scripts
About

Shell scripting involves writing a series of command for the shell to execute. It combines lengthy and repetitive sequences of commands into a single script, which can be stored and executed anytime. This reduces the effort required by the end user and the number of human mistakes.

You will write your first shell script and delve into the shell, to touch the power CLI which provides against the GUI. Also you will learn simple arguments and use getopts to make it a real Shell command. Then you will learn looping and functions for performing complex operations. You will then master Regex and regular expressions to validate your arguments. Finally, you will learn to write logs correctly and fight the temptation to use I/O redirections.

By the end of this course, you will be an expert at creating powerful shell scripts and will have explored the full possibilities of shells.

Style and Approach

This course starts with the simplest possible concept—listing the content of a folder—and leads you to an understanding of what a Linux OS System call is. You will see how programs interact with the OS, and what happens under the hood when you run a script of your own. You will solve tasks in the wrong way first and then learn to do so correctly, with the chance to compare using I/O redirection and the logger utility to write your own logs. The author will ask the question "What will happen?" before firing a command for a concept that has just been explained; that will be your queue to hit the Pause button and think.

Features
  • Avoid over-engineering; in most cases there is always a simple solution
  • Understand the internals; everything is based on simple concepts
  • Learn to debug and debug to learn
Course Length 2 hours 14 minutes
ISBN 9781789131208
Date Of Publication 30 Nov 2018
Shell Commands- Commands Are Built-In Scripts
Documentation- Reading the Man Pages
The First Shell Script – Using Shell Commands in the Scripts
Calling the Shell Scripts – Different Ways to Call the Same Script
The First Argument – The Path of the Script
The Order of the Arguments – Order Matters!
Types of Arguments – Strings, Numbers, and Special Characters
Parsing the Arguments – getopts
File I/O – Reading from a File and Writing to a File
Detaching from the Shell – Screen Utility and the &
Rewriting and Appending – The First Log
Environmental Variables – Playing with the PATH
Function Variables – Passing Arguments and Returning Values
Variable Scopes – It Is Not the Same Everywhere
Overloading – Redefining the Shell Commands
Naming – Naming Conventions
Branching – if/then/else and Case
Combining Loops and Branches – Nested Loops and Branches
Branching and Arguments – An Example init Script
Title
Regex – Introduction to Regex
Regex Flavors – It Is Not the Same Everywhere
Globbing – Globbing Is Not Regex
Practice – Practicing Is the Only Way
Logging – Use Logger to Write Your Logs
Reading the Logs – cut, tail, head, and grep
System Calls – What strace Shows
The Last Call – Putting It All Together

Authors

Paul Olushile

Paul Olushile graduated with a degree in Computer Science and is currently working as a Cyber Security Expert. He loves teaching and hence he has been freelancing for over 4 years and sharing his expertise with students as a Unix/Linux administrator. He has a diverse set of certifications, interests, and experiences including server administration.