BASH Scripting
#SWIFT
sareebro
What is a shell script?
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Script: a writing; a written document –
Webster's Dictionary
A shell script is an easy-to-use tool for
application building that “glues together”
system calls, tools, utilities, etc.
Shell Scripts can invoke the commands
available in Linux.
Why?
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Useful tool for System Administrators
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Avoid having to retype repetitive commands
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Scripts become a program – a tool that can
easily be customized for a particular
application
How? #!/bin/bash
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Start with a sha-bang (#!)
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Placed at the head of a script
#! is a two-byte magic number
designating the file type (or
executable shell script)
Tells your system that this file is a set
of commands to be fed to the
command interpreter indicated
Chmod then execute
• Change mode: command lets a user tell the
system how much access it should permit a
file
• Make the BASH script executable
chmod +x myscript.sh
• Execute your script (dot-slash)
./myscript.sh
Demo
We shall now make a simple BASH script!