Note that in some Unix systems, users are allowed to chown()
on their own files, and "give them away". And on most (if not
all) Unix systems, users are allowed to "chgrp" files provided
- Own the file.
- Are a member of the current group owner of the file.
- Are a member of the new group owner of the file.
Several years ago, I wrote the "chmod" command of the Perl
Power Tools (PPT). It was interesting to see that "chmod"
was implemented differently on all Unix systems I tested
(and often, the manual differed from the implementation as well).
Figuring out what chmod = file does depending on
the permissions of the file (or directory) on the various operating
systems was interesting.