ERROR: invalid locale name: "en_US.UTF-8" code example

Example: ERROR: invalid locale name: "en_US.utf8" on mac

sudo localedef -i /usr/share/locale/en_US.UTF-8 /usr/local/share/locale/en_US.utf8
sudo cp /usr/share/locale/en_US.UTF-8/LC_COLLATE /usr/local/share/locale/en_US.utf8/