chown

TLDR

Change owner

$ chown [user] [file]

Change owner and group

$ chown [user]:[group] [file]

Recursive change

$ chown -R [user]:[group] [directory/]

Change group only

$ chown :[group] [file]

SYNOPSIS

chown [options] owner[:group] file...

chown (change owner) modifies file ownership. It can change the user owner, group owner, or both. File ownership determines who has ultimate control over file permissions.
The command typically requires root privileges to change ownership to other users.

PARAMETERS

-R, --recursive

Change files and directories recursively

-v, --verbose

Verbose output

-c, --changes

Report only changes

--reference=file

Use ownership from reference file

-h, --no-dereference

Affect symbolic links instead of targets

--from=currentowner_

Change only if current owner matches

OWNERSHIP FORMAT

user

Change user owner only

user:group

Change user and group

user:

Change user and set group to user's login group

:group

Change group only (same as chgrp)

WORKFLOW

$ # Change owner
sudo chown alice file.txt

# Change owner and group
sudo chown alice:developers file.txt

# Change owner, group to user's login group
sudo chown alice: file.txt

# Change group only
sudo chown :www-data file.txt

# Recursive change
sudo chown -R alice:developers project/

# Use reference file
sudo chown --reference=template.txt newfile.txt

# Change only if owned by specific user
sudo chown --from=bob alice file.txt

COMMON USES

Web server files:

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

User home directory:

$ sudo chown -R alice:alice /home/alice

Restore ownership:

$ sudo chown -R $(whoami):$(whoami) ~/myproject

CAVEATS

Usually requires root/sudo. Changing ownership removes some security features (like setuid). Recursive changes can break system files. Cannot change ownership to users that don't exist. Symbolic links handled differently depending on options.

HISTORY

chown has been part of Unix since the early 1970s as part of the file ownership security model.