perl -se "BEGIN{print qq(inside BEGIN  \@ARGV is [@ARGV]\n)};print qq(inside main   \@ARGV is [@ARGV] and \$test is [$test]\n);" 
             -- -test=SET_VIA_-s arg1

    inside BEGIN  @ARGV is [arg1]
    inside main   @ARGV is [arg1] and $test is [SET_VIA_-s]