Set (Configuration command)
set [variable [value]]
Used by itself, 'set' lists all environment variables which have been
set. With just a variable name as an argument, it will set the value of
that environment variable to "" (an empty text).
If given a second argument, a value, a variable is created with that
name and that value if it doesn't exist. If it already exists, the old
value is replaced with the new one. This works for emotes as well.
You can see the list of all variables you can set in 'help sets'.