The “warning: setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory” error message in the OS X Terminal can occur when the system’s locale settings are not set correctly.
To fix this, you can try setting the locale to “UTF-8” using the following command in the Terminal:
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
This will set the locale to “UTF-8” for the current terminal session. If you want to make this change permanent, you can add the above two export statements to your shell startup file, such as .bashrc, .bash_profile, or .profile, depending on your shell.
If the problem persists, you may also try reinstalling the locale data by running the following command:
$ sudo locale-gen en_US.UTF-8
$ sudo dpkg-reconfigure locales
After running the above commands, log out and log back in for the changes to take effect.