[clug] Username

Rodney Peters rodneyp at iinet.net.au
Mon Sep 19 22:47:06 UTC 2016

I suggest that the link is correct:

lower case only permitted (anywhere)

must start with alpha character

underscore is the only non-alphanumeric permitted (many others have 
special meaning in Unix)

Obscure usernames might be more trouble than those are worth. Sys Admins 
probably have enough work resetting people's forgotten obscure passwords 
without having to remind someone of their username.

It is also worth checking the convention for passwords.  Starting a 
password with some specific special characters will cause problems.


On 20/09/16 03:42, Bryan Kilgallin wrote:
> I received a hand-me-down laptop. Set up with a simple and guessable 
> username. So now I want to replace the latter.
> I recall that passwords were supposed to be strange. Is such 
> applicable to usernames as well?
> I wanted an idea of rules and conventions. So I found the following. 
> What's that about starting lowercase? And I read somewhere else that 
> `.' was forbidden.
> {([a-z_][a-z0-9_]{0,30}) reads as "a lowercase or underscore, followed 
> by zero to thirty alphanumeric characters", meaning the total length 
> of the username can be 31 characters.}
> http://stackoverflow.com/questions/6949667/what-are-the-real-rules-for-linux-usernames-on-centos-6-and-rhel-6 

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