use strict;
use warnings;

my ($i, @arr, $separator, @lengths, $length, $format);

@arr = (
    ['', qw/COL1 COL2 COL3 COL4/],
    [qw/COL1 once upon a time/],
    [qw/COL2 there was a little/],
    [qw/COL3 table of data/]
);
$separator = ' | ';

for (@arr) {
    for $i (0..$#$_) {
        $lengths[$i] = length($_->[$i]) if !$lengths[$i] || $lengths[$i] < length($_->[$i]);
    }
}
$length = 0;
$length += $_ for @lengths;
$length += length($separator) * $#lengths + 4;

$format = join $separator, map { '%-'.$_.'s' } @lengths;
print '-' x $length, "\n";
print '| ', sprintf($format, @$_), ' |', "\n",
      '-' x $length, "\n" for @arr;