running some programs will give this result , this is happened with different applications one of them
vrms will give this issue:
user@host:~$ vrms perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = "", LC_ALL = (unset), LANG = "en_US.UTF-8" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). No non-free or contrib packages installed on host! rms would be proud. user@host:~$
something needs to be installed ? or we just ignore it?