Let's say i have a directory, at:
And inside got several recursive directories and files created by DIFFERENT USERS before.
So now, suddenly how do i make that above directory to be writable by root only?
Which means, the existing whatever users won't be suddenly able to write at all (but read only). So then only
root will be able to write any further.
Very importantly, i can NOT lose the original ownership (who owns what) of the things inside.
Which also means, after all, i am trying to LOCK the directory for security reason.