Book Image

Linux Shell Scripting Bootcamp

By : James K Lewis
Book Image

Linux Shell Scripting Bootcamp

By: James K Lewis

Overview of this book

Linux Shell Scripting Bootcamp is all about learning the essentials of script creation, validating parameters, and checking for the existence of files and other items needed by the script. We will use scripts to explore iterative operations using loops and learn different types of loop statements, with their differences. Along with this, we will also create a numbered backup script for backup files. Further, you will get well-versed with how variables work on a Linux system and how they relate to scripts. You’ll also learn how to create and call subroutines in a script and create interactive scripts. The most important archive commands, zip and tar, are also discussed for performing backups. Later, you will dive deeper by understanding the use of wget and curl scripts and the use of checksum and file encryption in further chapters. Finally, you will learn how to debug scripts and scripting best practices that will enable you to write a great code every time! By the end of the book, you will be able to write shell scripts that can dig data from the web and process it efficiently.
Table of Contents (19 chapters)
Linux Shell Scripting Bootcamp
Credits
About the Author
Acknowledgement
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Creating new commands from a template


Since you are reading this book it can be assumed that you are going to be writing a good number of scripts. Here is another handy trick I learned over the years. When I need to create a new script, instead of doing it from scratch I use this simple command:

Chapter 10 – Script 2

#!/bin/sh
#
# 1/26/2014
#
# create a command script

if [ $# -eq 0 ] ; then
 echo "Usage: mkcmd command"
 echo " Copies mkcmd.template to command and edits it with kw"
 exit 255
fi

if [ -f $1 ] ; then
  echo File already exists!
  exit 2
fi

cp $BIN/mkcmd.template $1
kw $1
exit 0


And here is the contents of the $BIN/mkcmd.template file:
#!/bin/sh
#
# Date
#
if [ $# -eq 0 ] ; then
 echo "Usage:                "
 echo "                      "
 exit 255
fi

Be sure that after you create the mkcmd.template file that you run chmod 755 on it. That way you do not have to remember to do it every time on your new commands. In fact, that was the main reason I wrote this script.

Feel free...