How to Use chgrp (Change Group Ownership) Command in Linux

In Linux, each file and directory is associated with a user and group owner to decide which user and group can read, write and execute the file and directory.

The chgrp command is used to change the group ownership of files and directories on Linux. Unlike the chown command, the chgrp command just requires you to specify a group name.

Prerequisites

• A server running Linux on the Atlantic.Net Cloud Platform

• A root password configured on your server

Create Atlantic.Net Cloud Server

First, log in to your Atlantic.Net Cloud Server. Create a new server, choosing any Linux operating system with at least 1GB RAM. Connect to your Cloud Server via SSH and log in using the credentials highlighted at the top of the page.

Basic Syntax of chgrp Command

The basic syntax of the chgrp command is shown below:

chgrp [option] groupname file/directory

A brief explanation of each option is shown below:

• -c Display verbose output only after the change is made.

• -f Suppress most error messages

• -v Show diagnostic for every processed file.

• -R Apply ownership on files and directories recursively.

• –help Used to display help information.

Display Group Ownership Of a File

Before changing the group ownership of any file and directory, it is important to know how to show the existing group ownership of any file and directory.

You can use the ls -l command to display the exiting group ownership of any file and directory:

ls -l hitesh.txt

This will display the group ownership of the file hitesh.txt, as shown below:

-rw-rw-r-- 1 root vyom 0 Mar 15 09:48 hitesh.txt

As you can see, vyom is the group owner of the file hitesh.txt.

Change Group Ownership Of a Directory

You can use the following syntax to change the group ownership of the directory:

chgrp groupname directory-name

For example, to change the group ownership of the directory /var/www to www-data group, run the following command:

chgrp www-data /var/www

You can use the -R flag with the chgrp command to change the group ownership of the specified directory including all sub-directories:

chgrp -R www-data /var/www

Change Group Ownership Of a File

Use the following syntax to change the group ownership of a file:

chgrp groupname file-name

For example, to change the group ownership of the file hitesh.txt to sudo group, run the following command:

chgrp sudo hitesh.txt

If you want to change the group ownership of multiple files, run the following command:

chgrp sudo file1 file2 file3

Copy Group Ownership From a Reference File

The chgrp command also allows you to copy the group ownership information from a reference file. The basic syntax to copy the group ownership is shown below:

chgrp [OPTION] --reference=[RFILE_NAME] [FILE_NAME]

For example, to copy the group ownership from the file named hitesh.txt to vyom.txt, run the following command:

chgrp --reference=hitesh.txt vyom.txt

Display chgrp Execution Information

You can use the chgrp command with the -c option to display a list of changes chgrp has made to each file specified.

For example, to see the changes that happened in the /var/www/html directory, run the following command:

chgrp -c -R sudo /var/www/html

You should see all changes made by chgrp command in the following output:

changed group of '/var/www/html/index.html' from root to sudo
changed group of '/var/www/html/index.nginx-debian.html' from root to sudo
changed group of '/var/www/html/example.com/index.html' from root to sudo
changed group of '/var/www/html/example.com' from www-data to sudo
changed group of '/var/www/html' from root to sudo

Conclusion

In this post, we explained how to use the chgrp command to change the group ownership of a file or directory. We also used some options with the chgrp command to customize the process. Hopefully, this post will help you in a multi-user environment.

Source: atlantic.net

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