linux issue: cannot change locale (en_US.UTF-8)

issue(ubuntu login message):

-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

resolve:
echo "LC_ALL=en_US.UTF-8" | sudo tee -a /etc/environment > /dev/null
echo "en_US.UTF-8 UTF-8" | sudo tee -a /etc/locale.gen > /dev/null
echo "LANG=en_US.UTF-8" | sudo tee /etc/locale.conf > /dev/null
sudo locale-gen en_US.UTF-8