Environment variables are very important aspect of Linux based operating systems. They are used by system to adjust its own behavior according to what you have specified during operating system installation and after that you can use it to tweak you system even more. Environment variables take form of name=value and you can view list of current environment variables by issuing following command on your favorite Linux terminal:

printenv

Some environment variables are set by the root user for all users on one PC, but every one of those users can have its own environment variables. Now lets see how should we assign lets say "en_US.UTF-8" value to environment variable named "LC_ALL" (by the way this is the way to tweak you environment locale setting for things like time and date format and things like that). Typically you will assign environment variable like this:

export LC_ALL=en_US.UTF-8