Sorting multiple keys with Unix sort

Question

I have potentially large files that need to be sorted by 1-n keys. Some of these keys might be numeric and some of them might not be. This is a fixed-width columnar file so there are no delimiters.

Is there a good way to do this with Unix sort? With one key it is as simple as using '-n'. I have read the man page and searched Google briefly, but didn't find a good example. How would I go about accomplishing this?

Note: I have ruled out Perl because of the file size potential. It would be a last resort.

Answer 1

Use the -k option (or --key=POS1[,POS2]). It can appear multiple times and each key can have global options (such as n for numeric sort)