Usage:
/split args
Sets %{P1} to the substring of args before the first '=', and sets %{P2} to the substring of args after the first '='. If there is no '=' in args, %{P1} will contain the entire string and %{P2} will be empty. %{P0} will contain the entire string.
Spaces surrounding the '=' are stripped.
See: getopts()