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Linux Bash Scripting for Beginners: Write Your Own Scripts

Name: Linux Bash Scripting for Beginners: Write Your Own Scripts
Rating: 4.1 (48 reviews)

Make your work easier, understand bash scripts written by others and build your own from scratch

Created byAndrei Bunghez

Last updated 6/2016

English

What you'll learn

Create and understand bash scripts.
Automate tasks in the Linux environment
Create a simple network monitoring utility in Linux
Schedule tasks to be run on a Linux system by using crontab
Define and use variables and functions in a bash script
Use basic Linux command line tools
Redirect output of command line tools using I/O redirection and pipes
Understand command substitution in the Linux command line environment
Many job ads list shell scripting as one of their requirements. Your chances in landing one of these will significantly increase

Course content

8 sections • 32 lectures • 2h 33m total length

Introduction2:00
Introductory lecture: find out how this course is structured and who is its intended audience.
How to Use This Course1:37
Brief overview about how this course works and quick glimpse at the Udemy interface.

Utilities Used in This Section6:10
This lecture briefly describes the utilities used throughout the course and shows you some basic uses.
Script Structure4:46
Going over the basic script structure, how to write comments, define and call functions.
Variables and the Environment9:39
This lecture shows you how to define and use variables.
Variables and Expansion
Script and Function Parameters6:37
Arguments are the way a script receives data from the outside world. This lecture goes over how you can access parameter values and manipulate them.
Parameters Quiz
Input/Output Redirection5:35
This lectures teaches you how to write output to a file, instead of the screen; and how to read input from a file, instead of the keyboard.
Pipes3:14
Pipes are a very powerful feature of the shell. This lecture shows you how to use them.
Command Substitution4:21
The fun part of using bash begins with command substitution. In this lecture you are going to learn how to replace a command name with its output.
Recap
if11:08
This lecture covers the 'if' statement and the syntax of the associated condition.
case5:51
To avoid using multiple if/else if/else statements, use the 'case' statement, that matches an input expression to one of the given patterns.
while/until5:50
This lecture covers the while/until loops.
for14:38
Both forms of the 'for' loops, C-like and lists, are described in this lecture.

Project Goals0:28
This document describes the ifMonitor project goals.
The check_iface Script: Extracting the Parameters5:41
This is the first lecture on the check_iface script, the "core" of the ifMonitor project. This first part shows you how to parse the command line parameters of the script.
The check_iface Script: Output Data9:42
In this second lecture on the check_iface script, one line of data is written to the output file.
cron & crontab5:42
cron & crontab are used to schedule tasks at a specified time.
The ifMonitor Script14:00
Using crontab to schedule the check_iface script.

The proc Filesystem3:14
Short overview on the proc filesystem. We will use files under this folder for the next lectures.
find8:21
This lecture is about find and gives you an example of how to use it to search for files.
Mysterious if
Mystery Explained0:51
Explanation for the question in the previous quiz.
find Some More
xargs4:21
xargs - an utility that lets you call other commands with parameters determined at runtime (as outputs of other commands)
xargs Quiz

General Rules1:00
General challenge rules
December '15 Challenge - Host Monitor2:00
Build an application that monitors the ping response time of several hosts.
January '16 Challenge - File Spacer1:00
Build a small tool that equally spaces lines in a file.
March '16 Challenge - Textify2:32
Create a script that receives one integer parameter and converts it to text.
Benefits:

practice arithmetic expansion

practice the case instruction

practice the if conditional expression with integers

good use of command substitution

the use of functions
June '16 Challenge - Letter Counter0:32
Create a simple script that counts the occurrences of a letter inside a text file.

Check the bash manual (man bash) - the Parameter Expansion section - on how to find the length of a variable or how to get a substring (even of length one) from a word.

December '15 Challenge Solved7:53
This lecture will show you how to resolve the host monitor challenge. Besides that, you will take a quick look at getopt, check out a faster way to schedule recurring tasks using crontab and find out how to use the last command error status ($?).

You can download the scripts for this challenge, they are attached to this lecture.
January '16 Challenge Solved2:22
Solving the file spacer challenge. This lecture will give you a quick insight into the workings of the IFS builtin variable.

Requirements

You need a linux pc/virtual machine
A text editor of your choice. I'm using text mode emacs, but nobody is forcing you to live in the past as well.
The bash shell

Description

Have you ever been frustrated by that script that just did not work? Are you tired of searching the web for a ready-made script, hoping that it will fix your problem? Want to sit back and relax for a couple of seconds while your script performs the task that would have taken you two hours to accomplish manually? Then you have come to the right course!

This course will help you build your own scripts and understand the ones written by others. No more relying on scripts that others built and hoping that they will solve your custom problems. Just writing your own solutions to your own problems.

Take this course to get:

Learning by example, so that instead of going through boring theoretical concepts, you get to see exactly how each concept applies in practice.
Monthly challenges to help you gain experience and trust in your own abilities.
Interactive, supportive experience, as I promptly reply to your questions when things just don't work.
30-day money back guarantee if you don't like this course for any reasons, no questions asked.

In short, you will learn the basic building blocks of bash, watch how a real-life utility is built, do the monthly challenges and solve coding problems in the discussion area to gain experience (did I mention the prizes?).

The first section covers basic building blocks that allow you to write your own shell scripts, which are presented in a learn-by-example fashion. Here you will learn about basic linux command line utilities used throughout the course, a simple script structure, defining functions, using input/output redirection, pipes and command substitution. The last lectures in this section focus on control statements, like if, case, while and for.

In the second section I will show you how to build a simple real-life utility for monitoring the amount of traffic on a network interface. There are two scripts involved in this utility. The "core", that queries system data about a network interface and adds it to a comma-separated-values (csv) file, one line at a time. The other one will take care of scheduling the "core" to be run at specific times, based on a user specified interval. The result is a csv file that contains data collected at specific points in time, data that can be later processed into a spreadsheet application (e.g. build graphs from it).

The rest of the course, what I call the dynamic part, is built in time. You will find here lectures on various command line utilities (e.g. find) or more in-depth lectures on subjects like redirection. I also post monthly challenges for you to gain some much needed experience, in order to ascend from a beginner to an intermediate level.

==========================================================

**** Monthly challenges (with prizes) ****

Jun '16: Utility to count the occurrences of a letter inside a text file

Mar '16: Textify, an utility that takes an integer number and converts it to text

Jan '16: Utility to equally space lines in a text file

Dec '15: Host ping reply time monitor

==========================================================

Update History

May 22nd 2016: Published solution for the January challenge

Feb 29th 2016: Published solution for the December challenge

Jan 3rd 2016: New lecture on xargs

Nov 22nd 2015: New section on standard end error output redirection

Nov 15th 2015: New lectures on the find utility and the proc filesystem.

Oct 10th 2015: New quiz on parameters

Who this course is for:

Junior software/network/QA engineers or students who would like to learn to use the linux bash shell efficiently
To make best use of this course you should take the time and work on the included challenges and exercises and take advantage from the interaction with your instructor. Just going through the materials can be done for free if you search deep enough.
If you are already familiar with bash scripts and linux command line utilities, this course is probably NOT for you

Linux Bash Scripting for Beginners: Write Your Own Scripts

What you'll learn

Explore related topics

Course content

Introduction2 lectures • 4min

Basic bash Building Blocks11 lectures • 1hr 18min

The ifMonitor Project - Monitoring a Network Interface5 lectures • 36min

findutils - find, xargs, locate4 lectures • 17min

[Updated] Cheatsheet1 lecture • 3min

More on redirection2 lectures • 6min

Challenges5 lectures • 7min

[New] Challenge Solutions2 lectures • 10min

Requirements

Description

Who this course is for: