Path: utzoo!attcan!uunet!cs.utexas.edu!usc!ucsd!rutgers!orstcs!sapphire!pvo
From: pvo@sapphire.OCE.ORST.EDU (Paul O'Neill)
Newsgroups: comp.lang.perl
Subject: Cute hack around tiny bug (Re: Help a perl apprentice)
Message-ID: <21380@orstcs.CS.ORST.EDU>
Date: 28 Oct 90 04:36:52 GMT
References: <18840001@hp-lsd.COS.HP.COM>
Sender: usenet@orstcs.CS.ORST.EDU
Reply-To: pvo@sapphire.OCE.ORST.EDU (Paul O'Neill)
Organization: Coastal Imaging Lab, Oregon State University, Corvallis, OR
Lines: 57

I really like Tim Chambers' df massager and Larry's rewrite of it.
-------------
#!/usr/local/bin/perl

open (BDF_PIPE, "bdf @ARGV |");

print <<End;
Filesystem                     Free (Mb) %Used
==============================|=========|=====
End

while (<BDF_PIPE>) {
    ($fs, $kbytes, $used, $avail, $capacity, $dirname) = split;
    next unless $kbytes > 0;
    # next unless $fs;          # uncomment to delete nfs filesystems
    $line{$avail} = sprintf("%30.30s%10.1f%6s\n",
                        $dirname . '.' x 30,
                        $avail / 1000, $capacity);
}

sub revnum { $b <=> $a; }

foreach $key (sort revnum keys(%line)) {
    print $line{$key};
}

print "\n";
----------------------

There's a tiny bug in there, though.

What if 2 file systems have the same available space? (ie. zero :-)

The old $line{$avail} gets wiped by the new $line{$avail} and is not
reported.

It occured to me that a good way to handle this was to add a small number,
say 0.1, to $avail if $line{$avail} aready existed.  But what if there were
*three* (or more) file systems with the exact same available space?

Hmm... What's a neat way of adding 0.1 to $avail recursively???

Bingo!! Don't bother.  Just add rand() to $avail!

      # next unless $fs;          # uncomment to delete nfs filesystems
+     $line{$avail} && $avail += rand;
      $line{$avail} = sprintf("%30.30s%10.1f%6s\n",

Hope you can use this some day ....

ps--the commented nfs remover just removes nfs mounts with long path's.


Paul O'Neill                 pvo@oce.orst.edu		DoD 000006
Coastal Imaging Lab
OSU--Oceanography
Corvallis, OR  97331         503-737-3251