Thanks !
That's great. But just to be sure, my loop

unless($perm++) {
     #Do the permutation
}
[download]

was done only once, wasn't it ?

Because, at first line, $perm is undef so evaluation of $perm++ is FALSE (and incremented) so the permutation is done, but after that, $perm++ is TRUE, so it isn't executed ? Is this wrong ? I'm quite sure it worked because a column was shuffled as a whole with that ??

But your script is really cool, and i didn't know i could make the output like that !

Marsel