Changing Ownership (chown)

The chown command changes file ownership. It's typically used by administrators to manage file access.

Basic Usage

chown owner filename
chown owner:group filename

Understanding Ownership

Every file has two owners:

1. User owner: A single user
2. Group owner: A group of users

-rw-r--r-- 1 alice developers 4096 Jan 7 file.txt
              │     │
              │     └── Group owner
              └── User owner

chown Syntax Options

chown user file           # Change user only
chown :group file         # Change group only
chown user:group file     # Change both
chown user: file          # User and their default group

Common chown Operations

Change Owner

chown alice file.txt

Change Group

chown :developers file.txt

Change Both

chown alice:developers file.txt

Exercise: Change Ownership

Change the owner of a file:

Recursive Changes

Change ownership of directory and all contents:

chown -R user:group directory/

chown Options

Option	Description
-R	Recursive
-v	Verbose
-c	Report only changes
--reference	Copy from another file

chown vs chmod

Command	Changes	Example
chmod	Permissions (rwx)	chmod 755 file
chown	Ownership	chown user:group file

Both affect who can access files, but differently:

• chmod: What actions are allowed
• chown: Who the file belongs to

Real-World Examples

Web Server Files

chown -R www-data:www-data /var/www/html/

User Home Directory

chown -R alice:alice /home/alice/

Shared Project

chown -R :developers /opt/project/
chmod -R g+w /opt/project/

Permission Requirements

Important: Only root (or sudo) can change file owners. Regular users can only change group to a group they belong to.

# As regular user - may fail
chown root file.txt           # Permission denied

# As root/sudo - works
sudo chown root file.txt      # Success

Related Command: chgrp

chgrp changes only the group:

chgrp developers file.txt
# Same as: chown :developers file.txt

Key Takeaways

• chown changes user and/or group ownership
• Use chown user:group for both at once
• Use -R for recursive changes
• Usually requires root/sudo privileges
• Different from chmod (which changes permissions)