Recipe 19.4 Changing File Permissions or Ownership
19.4.1 Problem
You want to change a
file's permissions or ownership; for example, you
want to prevent other users from being able to look at a file of
sensitive data.
19.4.2 Solution
Use chmod( ) to change the permissions of a file:
chmod('/home/user/secrets.txt',0400);
Use chown( ) to change a file's owner and
chgrp( ) to change a file's
group:
chown('/tmp/myfile.txt','sklar'); // specify user by name
chgrp('/home/sklar/schedule.txt','soccer'); // specify group by name
chown('/tmp/myfile.txt',5001); // specify user by uid
chgrp('/home/sklar/schedule.txt',102); // specify group by gid
19.4.3 Discussion
The permissions passed to chmod( ) must be
specified as an octal number.
The
superuser
can change the permissions, owner, and group of any file. Other users
are restricted. They can change only the permissions and group of
files that they own, and can't change the owner at
all. Nonsuperusers can also change only the group of a file to a
group they belong to.
The functions chmod( ), chgrp(
), and chown( ) don't
work on Windows.
19.4.4 See Also
Documentation on chmod( ) at
http://www.php.net/chmod, chown(
) at http://www.php.net/chown, and
chgrp( ) at
http://www.php.net/chgrp.
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