You’ll get the following error in Raspbian when locale is not properly set.

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

You can easily fix this via Raspberry Pi Software Configuration Tool (raspi-config) as in the following example;

  1. Run raspi-config from the command line.

    sudo raspi-config
  2. Choose Localisation Options from the main interface.
  3. Choose Change Locale from the menu.
  4. De-select locales that you don’t need (optional). en_GB.UTF-8 UTF-8 is installed by default and could be removed.
  5. Select en_US.UTF-8 UTF-8 from the list and press Ok.
  6. Select en_US.UTF-8 in the next screen
  7. The selected locales will be generated and you should no longer get the error.

    Generating locales (this might take a while)...
      en_US.UTF-8... done
    Generation complete.