$option_line = join ' ', @ARGV; #reconstitute
my @pairs = $option_line =~ m/(\w+:\s+\w+)/g; # grab option pairs
my %option;
for $pair (@pairs)
{
    # now split
    my ($name,$value) = split ":\s+", $pair, 2;
    # save each pair in hash
    $option{$name} = $value;
}