When trying to debug sendmail.cf files, it would be nice to have a short "cheet sheet" of the sendmail metasymbols. Well, I have a M4 template that will include a a quick reference guide to the sendmail metasymbols in your sendmail.cf File.

This M4 template can be found at ftp://ftp.harker.com/pub/sendmail/cf/cheatsheet.m4

To add the cheet sheet to your sendmail.cf file you would download the template either the hack or feature sub-directory of the sendmail-8.X/cf directory. If you were going to add the cheet sheat as a M4 HACK or FEATURE the file would be called:
   hack/cheatsheet.m4
or   feature/cheatsheet.m4
In your host.mc file

This template would be included in your sendmail.cf file by including:
   HACK(cheatsheet)
or   FEATURE(cheatsheet)
in your host.mc file.

Just another "Harker's Helpful Hints"