perlfaq nodetype
faq_monk
<P>
This is elaborately and painstakingly described in the ``Far More Than You
Ever Wanted To Know'' in <A
HREF="http://www.perl.com/CPAN/doc/FMTEYEWTK/file-dir-perms">http://www.perl.com/CPAN/doc/FMTEYEWTK/file-dir-perms</A>
.
<P>
The executive summary: learn how your filesystem works. The permissions on
a file say what can happen to the data in that file. The permissions on a
directory say what can happen to the list of files in that directory. If
you delete a file, you're removing its name from the directory (so the
operation depends on the permissions of the directory, not of the file). If
you try to write to the file, the permissions of the file govern whether
you're allowed to.
<P>