🚀 go-pugleaf

MW wrote:
> 
> Could someone please explain the SUID and SGID bits and how they relate
> to directories?
> Ive read that if u set the SGID bit on a directory then any files (and
> directories) created in that directory will have the group set to the
> group of that directory
> Is this correct?
> What happens when u set the SUID bit on a directory-does this do
> anything?
> Newbie-please help!!

SUID has no effect on directories.

SGID behaves as you have said.  This works in well with the RedHat
preferred method of setting up users in individual groups, and setting
the default umask to 002 (instead of 022).  If you are setting up a
directory hierarchy which you want shared with a given group, set the
group of the top dir to that of the sharing group, and set the mode to
SGID.  All files created under that dir will have the shared group id,
and by default, your umask of 002 will allow group writes to those
files.

The `sticky bit' is the equivalent bit on the `other' permissions.  On
linux, setting this bit on a directory prevents users from removing
files which they do not own, regardless of their write permissions on
the directory.  See, e.g., the default modes on the /tmp directory. 
Normally, if I have write permission on a directory, I can delete files
in that dir; I have write permission on /tmp, so normally I would be
able to delete any files found there.

Try this:

As root,
  touch /tmp/junk
  mkdir /tmp/rubbish
  chmod a+w /tmp/rubbish
  touch /tmp/rubbish/bin
  ls -ld /tmp /tmp/rubbish
  ls -l /tmp/junk /tmp/rubbish/*

As yourself (your non-root everyday user id, which of course, you use
most of the time)
  rm -f /tmp/junk
  rm -f /tmp/rubbish/bin

Yours faithfully,
-- 
 __ /__   Peter B. West  p.west@uq.net.au
   /     http://www.uq.net.au/~zzpwest
  /     "Lord, to whom shall we go?"