Script for File permission

We can explain the file permission by creating a simple script to execute and change the permission of the file after understanding file permissions. 

Step-By-Step commands in script: 

Step 1. First, we create a file or check if an existing file is there as mentioned in the screenshot. If the file is not present then we execute the command

   touch <FILENAME>    (this will create a new file)

Step 2.  Our aim is to remove the write permission of others and groups as mentioned in the screenshot we will execute the command in the script 

chmod 744 <FILENAME> 

Step 3. Finally, to check if permission is changed or not, we will use

ls -l 

The Script

#!/bin/bash

# script to change permission of file 

# File variable to store file.txt location 
FILE="file.txt"

# to check the file we want to change 
# exists or not
if [[ ! -e  "${FILE}" ]]
then
   echo "creating  ${FILE} file"
   touch file.txt
fi

# to remove  write permission of other and group of file
chmod 744 "${FILE}"

#to check if the permission are removed
ls -l  "${FILE}"

Now we will execute this script and check if it works 

./file_perm.sh

Output

NOTE: In writing script and executing it is important to check permission always after creating script ls  -l command 

In this article, we will discuss file permission in Bash Script

To understand the scenario let’s take an example. Let’s consider there is a system admin A for company XYZ he designs a script that is to be executed by a user at 8:00 PM daily to send a report. He designs the script but forgets to give permission to the user to execute the script. Whenever a user tries to execute a script, he gets the error You are not authorized to take this action so why did this happen?

In the above case, we see that the system admin created a script but he did not give permission to the user as he was unable to execute it so to go into depth about this let’s explain how can we set file permission and how to check them.

Solution:  Now for the above example the system admin only has to give or set the user file permission to execute so that he can execute that file