Sign In Start Free Trial
Account

Add to playlist

Create a Playlist

Modal Close icon
You need to login to use this feature.
  • Book Overview & Buying Linux Command Line and Shell Scripting Techniques
  • Table Of Contents Toc
  • Feedback & Rating feedback
Linux Command Line and Shell Scripting Techniques

Linux Command Line and Shell Scripting Techniques

By : Vedran Dakic, Jasmin Redzepagic
4.4 (5)
close
close
Linux Command Line and Shell Scripting Techniques

Linux Command Line and Shell Scripting Techniques

4.4 (5)
By: Vedran Dakic, Jasmin Redzepagic

Overview of this book

Linux Command Line and Shell Scripting Techniques begins by taking you through the basics of the shell and command-line utilities. You’ll start by exploring shell commands for file, directory, service, package, and process management. Next, you’ll learn about networking - network, firewall and DNS client configuration, ssh, scp, rsync, and vsftpd, as well as some network troubleshooting tools. You’ll also focus on using the command line to find and manipulate text content, via commands such as cut, egrep, and sed. As you progress, you'll learn how to use shell scripting. You’ll understand the basics - input and output, along with various programming concepts such as loops, variables, arguments, functions, and arrays. Later, you’ll learn about shell script interaction and troubleshooting, before covering a wide range of examples of complete shell scripts, varying from network and firewall configuration, through to backup and concepts for creating live environments. This includes examples of performing scripted virtual machine installation and administration, LAMP (Linux, Apache, MySQL, PHP) stack provisioning and bulk user creation for testing environments. By the end of this Linux book, you’ll have gained the knowledge and confidence you need to use shell and command-line scripts.
Table of Contents (19 chapters)
close
close

Local and global variables

When it comes to declaring any variable in a script—or for that matter, anywhere at all—one crucial attribute for that variable is its scope. By scope, we mean where the variable has the value we declared. Scope is very important since not understanding how it works means that we can get unexpected results in some cases.

Getting ready

Defining a global scope to our variables is something bash does by default, without any interaction with us. All variables that are defined are global variables; their value is the same in the entire script. If we change the variable value by reassigning it (remember that operations on the value do not change the value itself), this value changes globally, and the old value is lost.

There is another thing we can do when declaring variables, and that is to declare them locally. In simple terms, this means that we are explicitly telling bash that we will use this variable in some limited part of the code...

Unlock full access

Continue reading for free

A Packt free trial gives you instant online access to our library of over 7000 practical eBooks and videos, constantly updated with the latest in tech

Create a Note

Modal Close icon
You need to login to use this feature.
notes
bookmark search playlist font-size

Change the font size

margin-width

Change margin width

day-mode

Change background colour

Close icon Search
Country selected

Close icon Your notes and bookmarks

Delete Bookmark

Modal Close icon
Are you sure you want to delete it?
Cancel
Yes, Delete

Delete Note

Modal Close icon
Are you sure you want to delete it?
Cancel
Yes, Delete

Edit Note

Modal Close icon
Write a note (max 255 characters)
Cancel
Update Note

Confirmation

Modal Close icon
claim successful

Buy this book with your credits?

Modal Close icon
Are you sure you want to buy this book with one of your credits?
Close
YES, BUY