func main(file) {
    file.open_r(\var fh, \var err) ->
        || die "Can't open file `#{file}' for reading: #{err}\n";

    var vls = fh.words.group_by{.sort}.values;
    var max = vls.map{.len}.max;
    vls.grep{.len == max}.each{.join("\t").say};
}

main(%f'/tmp/unixdict.txt');