alfonsosanchezbeato@localhost:~$ sudo adduser --extrausers alfonsosanchezbeato audio
Adding user `alfonsosanchezbeato' to group `audio' ...
Adding user alfonsosanchezbeato to group audio
gpasswd: cannot lock /etc/group; try again later.
adduser: `/usr/bin/gpasswd -a alfonsosanchezbeato audio' returned error code 1. Exiting.