Getopt::Long::GetOptions(
    'f=s{1,}' => sub {
	foreach $_ (@_) {
	    if ($_ =~ /\.xls$/) {
		print "This is if \$_: ".$_."\n";
		push( @xls , $_ );
	    }
	    elsif ($_ =~ /^f/) {
		next;
	    }
	    else {
		die ("Invalid format for option expected -f '*.xls'\n");
	    }
	} # End of foreach
    },
    'p=s'     => sub {
	$_ = pop @_;
	/\.csv$/
	    or die ("Invalid format for option expected -p '*.csv'\n");
	$csv = $_;
    }
    )
    or usage("Invalid commmand line options.");