Various Linux programs will run an editor when necessary, and by
default the editor is vim. For example, your email program may invoke
an editor to compose a new message, and
less invokes an editor if you type “v”. But
what if you don’t want vim to be your default editor? Set the
EDITOR to your choice, for
$ EDITOR=emacs $ VISUAL=emacs $ export EDITOR VISUAL Optional
Both variables are necessary because different programs check
one variable or the other. Set
VISUAL in your ~/.bash_profile startup file if you want
your choices made permanent. Any program can be made your default
editor as long as it accepts a filename as an argument.
Regardless of how you set these variables, all system administrators should know at least basic vim and emacs commands in case a system tool suddenly runs an editor on a critical file.