Sendmail, 3rd Edition

V8 Comments

Beginning with V8 sendmail, all lines of configuration files of version levels 3 and above (Section 17.5) can have optional trailing comments. That is, all text from the first # character to the end of the line is ignored. Any whitespace (space or tab characters) leading up to the # is also ignored:

CWlocalhost mailhost  # This is a comment
                    ↑from here to end of line ignored

To include a # character in a line under V8 sendmail, precede it with a backslash:

DM16\[#megs]

Note that you do not need to escape the # in the $# operator. The $ has a higher precedence, and $# is interpreted correctly.