#!/usr/bin/perl5.003

#  A perl(1) program to df(1) and extract the pertinent directories, sum the
#  usages, convert the result to megabytes, and append the 'Mb' to it. Try it 
#  out just by running it.
#
#  Future versions of pibu(1) will use scripts that will be invoked with
#  parameters taken from the config file, so that we won't need a different
#  version of this program for each fileset.

open(PIPE_HANDLE, "df |") || die;
$spaceused = 0;
while (<PIPE_HANDLE>) {
    ($dev,$total,$used,$avail,$cap,$mounted) = split(/\s+/, $_);
     if ($mounted eq '/' || $mounted eq '/usr') {
         $spaceused += $used;
     }
}
close PIPE_HANDLE;
printf "%2d Mb\n", $spaceused / 1024;