Perl script to check free diskspace and email notification.

    #!/usr/bin/perl
    # Script to check free diskspace and email notifications.
    # Change the email and alert levels and you should be good to go.
    # Lazyman add this to cron @daily
    # This work on SunCellular network, it may also work on other network.
    # Edited: Christian Foronda
    # Last Edited: 07/30/2009

    use strict;
 
    # Alert levels Warning and Critical - Below what percent level of free disk space do you want an alert?
    my $alert1 = 20;        # Warning level free space below 30%
    my $alert2 = 10;        # Critical level free space below 10%
 
    # email address to notify
    my $email = 'admin at systmbx.com';
    my ($size,$used,$avail,$use,$mounted);
    my $message;
    my @message;
    my @list;
    my $sysname = `/bin/uname -n`;
    chomp $sysname;
    my @df = `/bin/df -h`;
    my $df;
    foreach $df (@df) {
     if ($df =~ /\/\n/) {
     @list = split(/\s+/, $df);
     }
     else {next;}
    }
 
    # Check the usage
    my $diskfree = (($list[3]) / ($list[2]+$list[3])) * 100.00;
 
    # Round the number off to 2 decimals
    $diskfree = sprintf("%.2f", $diskfree);
  
    # See if free disk space is below any of our levels
    if ( ($diskfree < $alert1) && ($diskfree > $alert2) ) {
     $message = "WARNING: Diskspace threshold reached...free space below $alert1% at $diskfree%\n";
     &mailer;
    }
 
    elsif ( ($diskfree < $alert1) && ($diskfree < $alert2) ) {
     $message = "CRITICAL: Diskspace threshold reached...free space below $alert2% at $diskfree%\n";
     &mailer;
     }
 
    else {
     $message = "Free diskspace is good at $diskfree%\n";
     }
 
    #Output to terminal (comment out if you wish)
    #print $message;
    #print "~" x 75, "\n@df","~" x 75,"\n","From system: $sysname\n";
 
    #Subroutine for Mail, notifies on warning and critical levels.
    sub mailer {

    # Uncomment if sendmail is preffered
    #        open(MAIL, "|/usr/sbin/sendmail -t") or die "Cannot open sendmail!: $!";
    #        print MAIL "To: $email\n";
    #        print MAIL "From: $sysname\n";
    #        print MAIL "Subject: $message\n\n";
    #        print MAIL "$message";
    #        print MAIL "~" x 75, "\n@df","~" x 75,"\n","From system: $sysname";
    #        close(MAIL);

    use Net::SMTP;

    my $relay = "xxx.xxx.xxx.xxx";
    my $smtp = Net::SMTP->new($relay)
     || die "Can't open mail connection: $!";

     $smtp->mail($sysname);
     $smtp->to($email);

     $smtp->data();
     $smtp->datasend("To: $email\n");
     $smtp->datasend("From: $sysname\n");
     $smtp->datasend("Subject: $message\n\n");
     $smtp->datasend("$message");
     $smtp->datasend("~" x 75, "\n@df","~" x 75,"\n","From system: $sysname");
     $smtp->dataend();
     $smtp->quit();
    }