perl: warning: Please check that your locale settings ubuntu

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = “en_US.UTF-8″,
LC_ALL = “en_US.UTF-8″,
LANG = “en_US.UTF-8″
are supported and installed on your system.
perl: warning: Falling back to the standard locale (“C”).
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory

This actually a pretty simple error that you'll encounter if there is a problem with your locale setting in Ubuntu (or maybe other Linux distro). Yet, it'll make you annoy to the max if you don't fix it.

This post is actually for my reference in the future if I encounter such problem again. The problem with me is that, I found a lot of same solution for this error, but all of it don't really shut that error message. The only one that works is below command:

$ export LANGUAGE=en_US.UTF-8
$ export LANG=en_US.UTF-8
$ export LC_ALL=en_US.UTF-8
$ locale-gen en_US.UTF-8
$ sudo dpkg-reconfigure locales

Credit: Hone Watson