dot allowed adduser/useradd

Alexander Dalloz alexander.dalloz at
Tue Feb 3 14:53:34 UTC 2004

Am Di, den 03.02.2004 schrieb Michael Schwendt um 14:06:
> On Tue, 03 Feb 2004 13:24:31 +0100, Alexander Dalloz wrote:
> > Dots are at least forbidden charactes in usernames and groupnames as
> > chown will fail with such names.
> That I don't believe. chmod can do
>   chown test
> as well as
>   chown test
> for user "" out of group "gfoo.gbar".

Ok, Michael, I tested this and it works so far. So in general to reject
creating users/group with dotted names is certainly either a historical
issue or - in present times - a protection against cases where you have
something like:

a user john.doe
a user john
a group doe

Or besides chown there might be problems with configurations from
/etc/security/ where permissions are set for users/groups. Or any other
applications causing trouble - just like upper letters in usernames for


Alexander Dalloz | Enger, Germany | GPG key 1024D/ED695653 1999-07-13
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