POSIX supports upper and lower case letters, however adduser is configured by default in Debian to only allow lower case. It makes sense for Unity Control Center to only allow lower case given it is used in Ubuntu, though GNOME Control Center might still continue to allow mixed case.
POSIX supports upper and lower case letters, however adduser is configured by default in Debian to only allow lower case. It makes sense for Unity Control Center to only allow lower case given it is used in Ubuntu, though GNOME Control Center might still continue to allow mixed case.