Nagios check for checking size of a file

check_file_size.pl

#!/usr/bin/perl

###  check_file_size.pl
# Based on check_backup.pl by Nathan Vonnahme
#

use strict;
use warnings;
use File::stat;
use Getopt::Long;

use vars qw($VERSION $PROGNAME $file $size $help);
$VERSION = '1.0';

# get the base name of this script for use in the examples
use File::Basename;
$PROGNAME = basename($0);

# II. Usage/Help
sub help() {
   print "Usage: $PROGNAME
    [ -f|--file=<path/to/file> ]
    [ -s|--size=<max size in MB> ]

  Examples:

    $PROGNAME -f /var/log/syslog -s 2048

  Check that /var/log/syslog exists, is below 2048 MB.
";
}

# Getopt::Long
GetOptions(
  'file|f=s', \$file,
  'size|s=s', \$size,
  'help|h=s', \$help);

# Print help if nothing is defined
unless (defined($file) && defined($size)) {
  help();
  exit -1;
}

# Check the backup file.
unless (-e $file) {
  print "File $file doesn't exist";
  exit 2;
}

# Calculate
my $mtime = File::stat::stat($file)->mtime;
my $age_in_hours =  (time - $mtime) / 60 / 60;
my $size_in_mb = (-s $file) / 1_000_000;

my $message = sprintf "Backup exists, %.0f hours old, %.1f MB.\n",
  $age_in_hours, $size_in_mb;


# Print output
print $message;

# Exit with error msgs
if ( $size_in_mb > $size ) {
  exit 2;
} else {
  exit 0;
}