adduser: Please enter a username matching the regular expression configured

win10上安装的ubuntu18，创建用户

具体报错如下：

$ sudo adduser Anne
adduser: 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.

解决方法：

把大写的首字母，改成小写即可。