~$:sudo vim /etc/default/locale
 LANG="en_US.UTF-8"                                                        
 LANGUAGE="en_US:en" 

~$:locale-gen
 Generating locales...
 en_US.UTF-8... up-to-date
 complete.

~$:locale -a
C
C.UTF-8
POSIX
en_US.utf8

~$:locale

LANG=
LANGUAGE=
LC_CTYPE="POSIX"
LC_NUMERIC="POSIX"
LC_TIME="POSIX"
LC_COLLATE="POSIX"
LC_MONETARY="POSIX"
LC_MESSAGES="POSIX"
LC_PAPER="POSIX"
LC_NAME="POSIX"
LC_ADDRESS="POSIX"
LC_TELEPHONE="POSIX"
LC_MEASUREMENT="POSIX"
LC_IDENTIFICATION="POSIX"
LC_ALL=