Prep reads each file in sequence and writes it on the standard output, one `word' to a line. A word is a string of alphabetic characters
and imbedded apostrophes, delimited by space or punctuation. Hyphented words are broken apart; hyphens at the end of lines are removed and
the hyphenated parts are joined. Strings of digits are discarded.
The following option letters may appear in any order:
-d Print the word number (in the input stream) with each word.
-i Take the next file as an `ignore' file. These words will not appear in the output. (They will be counted, for purposes of the -d
-o Take the next file as an `only' file. Only these words will appear in the output. (All other words will also be counted for the -d
-p Include punctuation marks (single nonalphanumeric characters) as separate output lines. The punctuation marks are not counted for
the -d count.
Ignore and only files contain words, one per line.