Thanks for the quidk reply. Please do send info about local arrangements. All I know is the dates. I read your shell assignment (but haven't yet looked at your program). It's a very good model of real life with Unix, particularly in regard to data laundry: automate what you can, but check the results. And that often feeds back into insight about further automation. I was once doing just such a job (in this case, trying to devise pronunciation rules for a text-to-speech system) when I got tired of using an editor to scan a dictionary that was too big to fit. I asked Ken Thompson if he could extract the editor's regular-expression recognizer into a free standing program. It turned out he had already done so for his own private use. Thus did grep make its appearance among Unix tools. Incidentally, you suggest using sed to get rid of carriage returns, disguised as ^M--very confusing because as a regular expression ^M means an M at the beginning of a line. The simplest solution I know is tr -d '\r'. For another revealing shell exercise you may like http://www.cs.dartmouth.edu/~doug/sieve.pdf. The shell stuff begins on page 4. Then comes truly lovely code in Haskell. Doug