Is a device currently up on LAN (determine if my phone is at home).

amihome.pl

#!/usr/bin/perl

use strict;
use warnings;

use Net::Ping;

my $file = "/tmp/amihome";
my $host = "192.168.2.127";

my $current;
if ( -r $file ) {
    open( my $in, '<', $file ) || die "Can't open existing file\n";
    while (<$in>) {
        chomp($_);
        $current = $_;
    }
    close($in);
}

my $p = Net::Ping->new();
my $new = $p->ping($host);
$p->close();

print $new . "\n";
unless (defined($current) && $current == $new) {
    open( my $out, '>', $file ) || die "Can't open output file\n";
    print $out $new;
    close $out;
    # Copy to server
    `scp -i /root/.ssh/no_pass /tmp/amihome jpm\@10.8.0.1:/tmp/new_amihome`;
}