chmod(1) - SerenityOS man pages


chmod - change file mode


$ chmod <octal-mode> <path...>
$ chmod <mode> <path...>


chmod changes mode of all files specified in path to octal-mode or using symbolic representation.

The symbolic representation format is [[ugoa][+-=][rwx...],...]. Multiple symbolic can be given, separated by commas.

The letters [ugoa] controls which users' access will be changes: u means file owner, g file owning group, o others, and a - all users. If no letter is given, a is assumed.

The letters [+-=] controls which action will be taken: + sets the permission, - removes the permission, and = sets the mentioned permissions and unsets the other permissions.

The letters [rwx] controls which permission will be changes: r is read, w is write and x is execute.

A numeric mode is combination of 1 to 4 numbers. Omitted digits are assumed to be leading zeros. The first digit select the set user ID (4), set group ID (2) and restricted deletion / sticky (1) attributes. The second, third and fourth digit controls permissions of each user group: owner, owning group and others (not owner or owning group), respectively: read (4), write (2) and execute (1).


# Allow full access for owner, read-execute for group, and no access for others, of '':
$ chmod 750

# Change '/bin/su' to be set-uid, read-write-execute for owner, only execute for others:
# chmod 4711 /bin/su

# Add read access for others to all files in 'Source' directory:
$ chmod o+r Source/*

# Deny read and write access for non-owners, and allow full access for owners of '':
$ chmod o-rw,g-rw,u+rwx

# Set group access to only read of '':
$ chmod g=r

See also