#!/usr/bin/perl

use strict;
use warnings;
use File::Basename;
use Getopt::Std;

my $name;
BEGIN { 
    $name = basename $0;
    sub USAGE () { <<".EOT"; }
$name [options]
      
Current options are:
      
    -m   Assume mc300, mc500 or mc700
    -h   Print this help screen and exit
.EOT
}

my %opts;
getopts 'mh' => \%opts;
print(USAGE), exit if $opts{h};

my $dir = '/usr/adm/private/memories';
my $olddf = 'olddf';

chdir $dir or die "[$name] Can't cd into `$dir': $!\n";
defined(my $newdf = qx/df/) or die "[$name] Can't run df: $!\n!";

my %oldused = map {
    my ($fs,undef,$used)=split;
    $fs =~ /:/ ? () : $fs => $used;
} do { 
    open my $df, '<', $olddf or die "[$name] Can't open `$olddf': $!\n";
    <$df> 
};

open my $df, '<', \$newdf or die "[$name] Can't open file in memory: $!\n";

while (<$df>) {
    my ($fs, $kbytes, $used, $avail, $capacity, $mounted_on) = split;
    next if $fs =~ /:/;
    my $oldused = $oldused{$fs};
    next if ($oldused == $used and $capacity < 99);	# inactive filesystem
    if ($capacity >= 90) {
        if ($opts{m}) {
            substr($_,13,0) = ' ' x 8;
            $_ /= 2 for $kbytes, $used, $oldused, $avail;
        }
	my $diff = int($used - $oldused);
        $mounted_on .= ' *' if $avail < 2*$diff;
	next if $diff < 50 && $mounted_on eq '/';
	$fs =~ s|/dev/||;
        $diff = '(' . ($diff >=0 ? '+' : '') . "$_)";
	printf "%-8s%8d%8d %-8s%8d%7s    %s\n" =>
          $fs, $kbytes, $used, $diff, $avail, $capacity, $mounted_on;
    }
}

open my $odf, '>', $olddf or die "[$name] Can't open `$olddf': $!\n";
print $odf $newdf;

__END__