Dear All, Thanks to the help I got from the list, I was able to (almost) finish a script that performs some data postprocessing (and the code is really amazingly short). Now, there are a few things left. Consider the lists bs = [4,5,3,1,5,2,7,2,8,2,2,3,3,5,6,7] and ms = [2,2,2,2,4,4,4,4,6,6,4,4,4,10,12,14] Now, I would like to sort bs (and that is easy) and then (since there is a 1-1 correspondence between the elements in ms and bs) re-order the elements in ms accordingly i.e. bs would become [1,2,2,2,2,3,3,3,4,5,5,5,6,7,7,8] and ms [2,4,4,6,4,2,4,4,2,2,4,10,12,4,14]. How can I achieve that? Finally, I would like to be able to save the two lists as plain text files (no commas, no brackets). I tried writeFile+Show, but this saves the lists exactly as printed on screen (whereas I simply would like a text file showing a column of numbers when opened by your favorite editor). Many thanks Lorenzo