#!/usr/local/bin/perl -w 

use strict;
use Sys::Hostname;

my ($fs, $kbytes, $used, $avail, $cap, $mount);
my $line;
my $host = hostname();
my $date = `date +%Y%m%d%H`;
my $outfile = "/export/home/steve/disk_log.$host.$date";
my $sendmail ='/usr/lib/sendmail -t ';

my $mailhdr = "To: steve\@foo.com\n".
    "Subject: Disk usage alarm - $host - $date\n======================================================\n\n";

open (OUTFILE, ">$outfile") || die "Can't open $outfile: $!\n";
print OUTFILE $mailhdr;
close (OUTFILE);

open (OUTFILE, ">>$outfile") || die "Can't open $outfile: $!\n";
my $cmd = `df -k /usr >> $outfile`;
close (OUTFILE);

open (OUTFILE, "$outfile") || die "Can't open $outfile: $!\n";
while ($line = <OUTFILE>) {
    chomp $line;
    next unless ($line =~ /^\//);
   ($fs, $kbytes, $used, $avail, $cap, $mount)   = split(' ', $line); 
    $cap =~ s/\%//;
   }
close (OUTFILE);  

if ($cap >= 50) {
    system( "$sendmail < $outfile") == 0 or die "Can't Mail: $!\n";
}
else {
    exit;
}