As tends to happen between milestone releases, utilities get changed in oh-so-subtle ways. This time, sort broke for me. That's right, sort! Of the things...
10.4 sort accepted the "plus notation" for denoting the position of the key that you wanted to sort on:
ls -l | sprt +5
(OK, terrible example as you can do this completely with ls itself, but, you get the idea).
In OS 10.5, that is gone, and you need the more formal "-k" switch:
ls -l | sort -k 4
Note that the plus notation is zero-based, and the k switch starts at 1.