Added in 1.9.0

$null

If a variable is referred to and it does not exist, it returns the value $null. The $null value can be used in comparisons in if-then-else statements to control branching etc.

Example

; Check if NonExistingNick is in the current channel.
//if ($nick(#, NonExistingNick) == $null) echo -ag NonExistingNick was not found