Cacti query unix partition

#!/usr/bin/perl

if (($ARGV[0] ne "query") && ($ARGV[0] ne "get") && ($ARGV[0] ne "index") && ($ARGV[0] ne "num_indexes")) {
        print "usage:\n\n";
        print "./query_unix_partitions.pl index\n";
        print "./query_unix_partitions.pl num_indexes\n";
        print "./query_unix_partitions.pl query {device,mount,total,used,available,percent}\n";
        print "./query_unix_partitions.pl get {device,mount,total,used,available,percent} DEVICE\n";
        exit;
}

open(DF, "/bin/df -P -k|");

$count=0;
while (<DF>) {
        #/dev/hda2             20157744  18553884    579860  97% /var
        if (/^(\/\S+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)%\s+(\/\S*)$/) {
                my %output = (
                        device => $1,
                        mount => $6,
                        total => $2,
                        used => $3,
                        available => $4,
                        percent => $5
                );

                if ($ARGV[0] eq "index") {
                        print "$1\n";
                }elsif ($ARGV[0] eq "num_indexes") {
                        $count++;
                }elsif (($ARGV[0] eq "get") && ($ARGV[2] eq $1)) {
                        print $output{$ARGV[1]};
                }elsif ($ARGV[0] eq "query") {
                        print "$output{device}:$output{$ARGV[1]}\n";
                }
        }
}

close(DF);

if ($ARGV[0] eq "num_indexes") {
        print "$count\n";
}