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Re: About valid and invalid user names



On Sath, 2005-02-05 at 13:38 +0100, Marc Haber wrote:
> Hi,
> 
> adduser has two bug reports open where people are asking for user name
> rules to be relaxed. One report wants "." to be allowed in user names,
> another wants usernames to start with numbers.
> 
> May I ask for your opinion before denying or following the requests?
> 
> Greetings
> Marc

The last time I looked, POSIX allowed '.' in usernames; it certainly
works for me where I use it, and allows sensible names that scale.
(fitting names like 'alastair.mckinstry' in ls -l is a different matter,
but it makes for usable login names; I work for an ISP and our usernames
and email names are 'firstname.lastname'; we don't give shell accounts,
though.

GNU chown has an extension of interpreting 'foo.bar' as username foo,
group bar. This is problematic. Fortunately it also supports the Correct
(TM) way of doing it, foo:bar . ':' is definitely not allowed in
usernames in POSIX.

I can dig out the actual spec, if necessary.

Regards
Alastair McKinstry



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