I'm changing my username on Ubuntu 14.04 as read on another question and I then get this message.
Please enter a username matching the regular expression configured via the NAME_REGEX[_SYSTEM] configuration variable. Use the `--force-badname' option to relax this check or reconfigure NAME_REGEX.
I have no idea what this means or if it's anything serious. Is it serious?
There is an answer here by CoalaWeb that may help you: https://askubuntu.com/a/232745/485705
"You normally get this message if you are trying to create a user with a name that contains characters that are considered to be un acceptable as per your NAME_REGEX file. You can try again changing the username with the GUI or you can relax the check by using the command line with the following command.
sudo adduser --force-badname <username>and then if you want to add the user to the sudo group run the following command.
sudo adduser <username> sudo"
There is more information about why NOT to use characters considered unacceptable in a reply by steveha here: https://serverfault.com/a/73101
"My advice to you is to follow the standard recommended by the default NAME_REGEX. You can actually put nearly anything in a user name under *NIX but you may encounter odd problems with library code that makes assumptions."
