On Tue, Dec 25, 2007 at 04:23:34PM +0100, Mike Lott wrote:
quoted text
> Hi list
> 
> I've been wondering why system accounts from UID 28 upwards are
> prepended with an underscore, whereas UID's in the range 0 up to 27 do
> not have this. I've done a bunch of searches on Google, but come up
> with nothing as yet.
> 
> Could anyone enlighten me?
> 
> Thanks,
> 
> Mike
> 

The ones from 0 to 27 are/were set in stone by long history. The _*
ones were introduced in OpenBSD as part of the elimination of
suid programs. By assigning a different account to each individual
system service the damage a broken service can do is minimized. By
prefacing them with _ a lot of namespace collisions are avoided and
it is obvious which ones are 'services' vs 'people'.

.... Ken