Perl warning about locale in Ubuntu

If you get this warning

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
 LANGUAGE = (unset),
 LC_ALL = (unset),
 LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

it can be fixed with

locale-gen en_US.UTF-8
dpkg-reconfigure locales