Chapter 8. Test Rule Sets with -bt

The sendmail program offers a mode of operation called rule-testing mode that allows you to observe the flow of addresses through rule sets. The -bt command-line switch causes sendmail to run in rule-testing mode. This mode is interactive. You enter rule set numbers or names, addresses, and other commands, and sendmail processes them and prints the results. The -bt switch’s chief use is in testing changes in the configuration file. It is also useful for learning how rules and rule sets work.


The following command runs sendmail in rule-testing mode:[141]

% /usr/sbin/sendmail -bt

At first, the output produced by this command line prompts you like this:

ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter <ruleset> <address>

The “ruleset 3” statement says that, beginning with V8 (and IDA) sendmail, the canonify rule set 3 is no longer automatically called when rule sets are listed at the prompt. We cover this property in detail in The Address on page 315.

Prior to V8 sendmail, rule-testing mode could be used only to test addresses. But beginning with V8.7 sendmail, new functions were added. To see a summary of those functions, enter a ? character followed by a RETURN at the > prompt. The output, which we reproduce next, lists and gives a brief description of each function. Note that the numbers to the right refer to sections in this chapter and are not a part of sendmail’s output:

> ? Help for test mode: ? :this help message. .Dmvalue ...

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