Some media organisations publish a "Target" word puzzle, where the objective is to find as many words as possible using the set of letters provided, and where every valid word must contain a particular letter.

Here's a link to another solver.

The Unix (including macOS) system dictionary is used and assumed to be in /usr/share/dict/words. Alternate dictionaries may be supplied.

$ ./targetfinder -help
Usage of ./targetfinder:
  -dictionary string
    	location of system dictionary file (default "/usr/share/dict/words")
  -key string
    	key letter. Must be exactly 1 character (default "t")
  -target string
    	target letters. Must be exactly 9 characters (default "dtgmtiaei")