Why are dots in username & groupname no longer allowed?

[redhat at barendse.to (Remco Barendse)]

> As far as I know, dots where never supposed to be valid characters for
> Unix usernames. The historical reasons are many, including the syntax
> of some commands that take username as a parameter. Several commands will
> that username.group as a parameter and, as you can see, the dot can
> get in the way of that.
>
> So, if you ask me, the upstream provider just corrected a long standing
> compatibility issue.

I think it's really a bug :

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=159034

but not something the upstream provider cares to fix it seems

> In any case, if you really want to have usernames with dots on it,
> you can create them manualy, or create them without the dot, and then
> change them by editing the apropriate files.

That's what I did now but I'm not very comfortable in editing /etc/shadow 
by hand


Thanks for the feedback!