And here's mine, which again cycles to pick the max number of columns possible. Note that both width and spacer width can be specified. 
use strict;

my $width = 80;
my $spacer = 2;
my @files = sort(split(/\s+/, join('', <DATA>)));

my ($pl, $c, $i, $j, $max, $total, @max, @sorted); 

while () {
    $pl = ($#files + 1) / ++$c;
    $pl = int $pl + 1 if $pl != int $pl;
    $total = 0;
    for ($i = 0; $i < $c; $i++) {
        $max = 0; 
        for ($j = 0; $j < $pl; $j++) {
            $max = length($files[$i*$pl+$j])
                if $max < length($files[$i*$pl+$j]);
        }
        $total += $max + $spacer;
    }
    last if ($width < $total - $spacer);
}

$pl = ($#files + 1) / --$c;
$pl = int $pl + 1 if $pl != int $pl;
for ($i = 0; $i < $c; $i++) {
    $max = 0; 
    for ($j = 0; $j < $pl; $j++) {
        $sorted[$j][$i] = $files[$i*$pl+$j];
        $max = length($files[$i*$pl+$j])
            if $max < length($files[$i*$pl+$j]);
    }
    $max[$i] = $max + $spacer;
} $max[$#max] -= $spacer;

for (@sorted) {
    $c = 0;
    print sprintf('%-'.$max[$c++].'s', $_) for (@$_);
    print "\n";
}

__DATA__
B           Digest      Filter     MIME       SDBM_File  Time     util
ByteLoader  DynaLoader  GDBM_File  NDBM_File  Safe       Unicode
Cwd         Encode      I18N       ODBM_File  Socket     XS
DB_File     Errno       IO         Opcode     Storable   attrs
Data        Fcntl       IPC        POSIX      Sys        re
Devel       File        List       PerlIO     Thread     threads

[download]

In reply to Re: 'ls -C' column style by TedPride
in thread 'ls -C' column style by hv

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.