The ultimate guide to mastering chmod in Linux

The Ultimate Guide to Mastering chmod in Linux

If you have been using Linux for a while, you must have come across the term „chmod“ many times. chmod is a command-line utility in Linux that stands for „change mode“ and is used to modify the user, group, and other permissions of a file or directory. Understanding how to use chmod is essential if you want to become proficient in Linux.

In this article, we will be discussing everything there is to know about the chmod command. From the syntax, meaning of file permissions, to some practical examples, this guide is your one-stop shop to mastering chmod in Linux.

Types of Permissions

Before we dive into chmod, you need to understand what file permissions are and the different types available. In Linux, there are three types of permissions:

Read (r): Enables you to read file contents.

Write (w): Gives you the power to modify the contents of the file.

Execute (x): Executes or runs a file.

Every file in Linux has three sets of permissions – owner, group, and others. Let’s say you have a file named „example.txt.“ File permissions determine who can read, write or execute the file.

Syntax of chmod

The syntax of chmod is:

chmod [OPTION]… {MODE | –reference=RFILE} FILE…

In this syntax, OPTION represents the various arguments you can pass into chmod. MODE refers to the permissions settings we want to set, and FILE represents the file you want to modify.

The MODE is a combination of the file permissions we have discussed above, combined with the permissions type you want to assign. To assign the read, write, and execute permissions to the owner, write and execute permissions to the group and execute permission to others, we can use the following command:

chmod 751 example.txt

Here, 7 refers to read, write, and execute permissions set for the owner, 5 for read and execute permissions for the group, while 1 refers to execute permissions for others.

Code Examples

Let’s look at some practical examples of how to use chmod on common Linux scenarios.

1. To change file permissions to only read and write, use:

chmod u+rw example.txt 

Here, u stands for owner, + for adding permissions, and rw for read-write permissions.

2. To add execute permissions to all users, issue:

chmod a+x

Here, a represents all users, + for adding permissions, and x for execute permissions.

3. To deny read and write access to others, but let owner have all permissions, use:

chmod o-rwx example.txt

Here, o stands for others, – for removing permissions, and rwx for read, write, and execute permissions.


In conclusion, chmod is an essential part of Linux command-line utilities that enables you to modify file permissions. Understanding how to use it can significantly improve your Linux experience. With this Ultimate Guide to Mastering chmod, you can now confidently use chmod in your day-to-day Linux workflows. So keep practicing, keep experimenting, and keep mastering Linux!