These files contain both DOS and UNIX versions of the Pascal code for the book. See notes above about extracting pkzipped files. Pascal interpreter for Mac. Files are stuffed and binhexed.
Some archives contain hundreds of files in many subdirectories.
Without that switch, pkunzip will attempt to place them all in a single directory. This may result in overwritten files, a cumbersome directory, or a failure to extract all files from the archive if file number limits are exceeded.