DebianでいっつもこのWarning出てて気になってた。
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = "en_US:en",
LC_ALL = (unset),
LC_CTYPE = "UTF-8",
LANG = "en_US.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
正しい直し方は多分これ。
$ vi sudo /etc/environment
LC_ALL=en_US.UTF-8
$ sudo reboot
日本語の場合はja_JP.UTF-8
にする。