Book Image

Learning Linux Shell Scripting

By : Ganesh Sanjiv Naik
Book Image

Learning Linux Shell Scripting

By: Ganesh Sanjiv Naik

Overview of this book

Linux is the one of the most powerful and universally adopted OSes. Shell is a program that gives the user direct interaction with the operating system. Scripts are collections of commands that are stored in a file. The shell can read this file and act on the commands as if they were typed on the keyboard. Shell scripting is used to automate day-to-day administration, and for testing or product development tasks. This book covers Bash, GNU Bourne Again SHell, preparing you to work in the exciting world of Linux shell scripting. We start with an introduction to the Shell environment and explain basic commands used in Shell. Next we move on to check, kill, and control the execution of processes in Linux OS. Further, we teach you about the filter tools available in Linux and explain standard output and standard errors devices. Then we will ensure you understand Shell’s interpretation of commands and get a firmer grasp so you use them in practice. Next, you’ll experience some real-world essentials such as debugging and perform Shell arithmetic fluently. Then you’ll take a step ahead and learn new and advanced topics in Shell scripting, such as starting up a system and customizing a Linux system. Finally, you’ll get to understand the capabilities of scripting and learn about Grep, Stream Editor, and Awk.
Table of Contents (20 chapters)
Learning Linux Shell Scripting
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Learning basic Linux commands


The following table lists a few basic Linux commands:

Command

Description

$ ls

This command is used to check the contents of the directory.

$ pwd

This command is used to check the present working directory.

$ mkdir work

We will work in a separate directory called work in our home directory. Use this command to create a new directory called work in the current folder.

$ cd work

This command will change our working directory to the newly created directory work.

$ pwd

This command can be used to verify whether we moved to the expected directory.

$ touch hello.sh

This command is used to create a new empty file called hello.sh in the current folder.

$ cp hello.sh bye.sh

This command is used to copy one file into another file.

This will copy hello.sh as bye.sh.

$ mv bye.sh welcome.sh

This command is used to rename a file. This will rename bye.sh as welcome.sh.

$ ll

This command will display detailed information about files.

$ mv welcome.sh .welcome.sh

$ ls

Let's see some magic. Rename the file using the mv command and the run the ls command.

Now, the ls command will not display our file .welcome.sh. That file gets hidden. Any filename or directory name starting with "." (dot) becomes hidden.

$ ls -a

This command is used to see hidden files.

$ rm .welcolme.sh

This command is used to delete the file.

Note

If we delete any file from GUI such as Graphical User Interface, then it will be moved to the /home/user/.local/share/Trash/files/ all deleted files folder.