LinuxQuestions.org - Case-insensitive User Name Creation

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Case-insensitive User Name Creation

Hello,

I am having a go at setting up an e-mail server using CentOS 6.2 running under VirtualBox. I have never done this before, only previously using Linux as a desktop OS.

So I installed CentOS, using a "minimal" install with the "E-mail Server" option selected. postfix and dovecot are available. I also installed mailx for testing.

I can send an e-mail to "root" and this will appear in /var/mail/root. However, after creating a user with my forum username and trying to send e-mail to that, nothing seems to happen. Examining /var/log/maillog shows that the e-mail bounced due to an unknown user "smurf7".

Reading around this, it seems that postfix converts the requested user name into lowercase before looking anywhere (putting "smurf7:SMurf7" into \etc\aliases and running newaliases didn't fix it). Short of butchering the code, there is little I can do about that.

Most people also infer that creating usernames with uppercase letters is bad form, yet adduser did not complain when I did it.

Is there a way that I can force adduser to treat all usernames as lowercase, preventing duplicate names in different case (and allowing e-mail to work)?

Well, you could make a wrapper:

lcadduser.sh (lowercase adduser):

Code:

#!/bin/bash



LCUSER=`echo $1 | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`

adduser $LCUSER

Code:

# lcadduser SMurf7

Or something like that. Though it's probably not the "proper" way to handle your problem.

No need to use tr for this in modern versions of bash. It has built-in case conversion.

Code:

#!/bin/bash

adduser "${1,,}"

parameter substitution

But first take a look at man adduser.conf for details on the NAME_REGEX value. According to mine, the default value is set to accept lowercase-only anyway.