Programming

#!/usr/bin/perl

use strict;
use warnings;
use Filesys::DiskSpace;

# file system to monitor
my $dir = "/opt";

# warning level
my $warning_level=10;

# email setup
my $to='mail@mail.com';
my $subject='Low Disk Space';

# get df
my ($fs_type, $fs_desc, $used, $avail, $fused, $favail) = df $dir;

# calculate 
my $df_free = (($avail) / ($avail+$used)) * 100.0;

# compare 
if ($df_free < $warning_level) {
my $out = sprintf("WARNING Low Disk Space on $dir : %0.2f%%  ()\n",$df_free);

# send email using UNIX/Linux sendmail
open(MAIL, "|/usr/sbin/sendmail -t");

## Mail Header
print MAIL "To: $to\n";
print MAIL "Subject: $subject\n";

## Mail Body
print MAIL $out;

close(MAIL);
}

>./test2.sh 
Can't locate Filesys/DiskSpace.pm in @INC (@INC contains:  /usr/lib/perl5/5.8.8/s390x-linux-thread-multi /usr/lib/perl5/5.8.8  /usr/lib/perl5/site_perl/5.8.8/s390x-linux-thread-multi  /usr/lib/perl5/site_perl/5.8.8 /usr/lib/perl5/site_perl  /usr/lib/perl5/vendor_perl/5.8.8/s390x-linux-thread-multi  /usr/lib/perl5/vendor_perl/5.8.8 /usr/lib/perl5/vendor_perl .) at  ./test2.sh line 5.
BEGIN failed--compilation aborted  at ./test2.sh line 5.

Can't call method "df" without a package or object reference at  ./test2.sh line 18.