codeword is released under the GPL v3.  See LICENSE for details.

words_alpha.txt is released into the public domain.  The original source and
license is available at https://github.com/dwyl/english-words.

To use codeword, run it with a text file containing a list of words and a
series of arguments that define whether each character position is a missing
letter (using period), a numbered letter or a fixed letter.

For instance:

    codeword words_alpha.txt 1 2 w 2

To search for a four letter word where 'w' is the third character, the first
charater is a different letter, and the same different letter is used in the
second and fourth character position.

    codeword words_alpha.txt . . w .

To search for a four letter where the third character is 'w' and all other
characters can be any letter.