Shell scripting basics

“Learn something new”

We all sometimes feel that there can be some machine which can do your work so that you can concentrate on more innovations. Shell scripting is one of the powerful techniques to automate your daily tasks.In Linux, bash scripting is one of the common shell which we can invoke from the command line.

We are going to see how to create,edit and execute a shell script in Linux.

We can use a vi editor to write a shell script.

In Linux terminal,give the following:

~]$ vi file_name

Every bash script starts with the line:

#!/bin/bash

where #! is called sharp + bang also called as shebang for invoking the bash executable from binary.

For example: I want to clean up the logfiles using a shell script for specific log directory for a every two days.I write a shell script like:

#!/bin/bash

find /path/to/files/ -type f -name '*.log' -mtime +2 -exec rm {} \; —-> give ‘shift key’ + : + wq to exit the vi editor

Give permissions to the file to execute:

chmod -R 755 filename

To execute a shell script:

use “./ + filename”

example: If your file is present in current working directory you have to use “./”

./filename

if your file is present in some other directory ,then set the variable $PATH as :

export PATH=/path/to/executable file

eg:export PATH=/bin/sqlplus

To check the path of the executable file

echo $PATH

We will see more in further posts.Thank you!!!

Published by kishan

You will know about me.

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