ownership
Change file or directory ownership
SYNOPSIS
chown [OPTION]... [OWNER][:[GROUP]] FILE...
PARAMETERS
-c
, --changes
Report only when a change is made.-f
, --silent
, --quiet
Suppress most error messages.-v
, --verbose
Output a diagnostic for every file processed.--dereference
Affect the referent of each symbolic link (this is the default), rather than the symbolic link itself.--no-dereference
Affect symbolic links instead of any referenced file.-h
, --no-dereference
Affect each symbolic link instead of any referenced file.--from=CURRENT_OWNER:CURRENT_GROUP
Change the owner and/or group of each file only if its current owner and/or group match those specified here. Either may be omitted, in which case a wildcard value is assumed.--preserve-root
Fail to operate recursively on '/'.--no-preserve-root
Do not treat '/' specially (the default).-R
, --recursive
Operate on files and directories recursively.--reference=RFILE
Use RFILE's owner and group rather than specifying OWNER:GROUP values.OWNER
Username or UID to set as the new owner.GROUP
Group name or GID to set as the new group. Omit GROUP to leave the group unchanged.
DESCRIPTION
The chown
command in Linux is used to change the ownership of files or directories. It allows you to modify which user and/or group is associated with a particular file, granting or restricting access as needed. This is a fundamental command for managing file permissions and security within a Linux environment. chown
is typically executed with superuser privileges (root) or by the current owner of the file.
Incorrect usage of chown
can lead to unintended security vulnerabilities, so it's crucial to understand its syntax and implications thoroughly. For example, changing ownership of system files without understanding consequences could lead to system instability or denial of service. Changing ownership might affect accessibility of configuration files, hence making programs non functional. The command is a cornerstone of Linux administration.
CAVEATS
Requires root privileges to change ownership of files you don't own. Be careful when using the recursive option on system directories. On some systems changing the group of a file may require ownership of the file.
EXAMPLES
chown user file.txt changes the owner of file.txt to user.
chown user:group file.txt changes the owner to user and the group to group.
chown :group file.txt changes the group to group but leaves the owner unchanged.
chown -R user:group directory recursively changes the owner and group of all files and subdirectories within directory.
HISTORY
chown
has been a fundamental part of Unix-like operating systems since their early days. Its purpose remains consistent: to provide a mechanism for managing file ownership and access control. Over time, the command's implementation has been refined, and additional features (like recursive operations) have been added. The command is standardized by POSIX.