8.3 Dump a sendmail Macro or Class

Beginning with V8.7, rule-testing commands allow you to print the value of a defined sendmail macro and the members of a class. With either command, you can use single-character or multicharacter macro names. Both commands begin with a $ character. An error is caused if nothing follows that $:

Name required for macro/class

If an = character follows, sendmail will display the requested class. Otherwise, the value of the sendmail macro is displayed:

$X          display the value of the X macro
$=X         list the members of the class X

8.3.1 Dump a Defined Macro with $

The $ rule-testing command causes sendmail to print the value of a defined sendmail macro. The form for this command looks like this:

$X           show value of the single-character macro name X
${YYY}       show value of the multicharacter macro name YYY

Only one sendmail macro can be listed per line. If more than one is listed, all but the first is ignored:

$X $Y
     
   ignored

One use for this command might be in solving the problem of duplicate domains. For example, suppose you just installed a new configuration file and discovered that your host was no longer known as here.our.domain but instead wrongly had an extra domain attached, like this: here.our.domain.our.domain. To check the value of $j ($j), which should contain the canonical name of your host, you could run sendmail in rule-testing mode:

ADDRESS TEST MODE (ruleset 3 NOT automatically invoked)
Enter <ruleset> <address>
> $j
$w.our.domain
>

This looks right because $w ($w) is supposed to contain our short hostname. But just to check, you could also print the value of $w:

> $w
here.our.domain

Aha! Somehow, $w got the full canonical name. A quick scan of your .mc file (Section 4.2) turns up this error:

LOCAL_CONFIG
Dwhere.our.domain           # $w is supposed to be full -- joachim

Apparently, your assistant, Joachim, mistakenly thought the new sendmail was wrong. You can take care of the configuration problem by deleting the offending line and creating a new configuration file. To solve the problem with Joachim, consider buying him a copy of this book.

8.3.2 Dump a Class Macro with $=

The $= rule-testing command tells sendmail to print all the members for a class. The class name must immediately follow the = with no intervening space, or the name is ignored. Both single-character and multicharacter names can be used:

$= X        the X is ignored
$=X         list the members of the class X
$={YYY}     list the members of the multicharacter class YYY

The list of members (if any) is printed one per line:

> $=w
here.our.domain
here
[123.45.67.89]
fax
fax.our.domain
>

To illustrate one use for this command, imagine that you just made the local host the fax server for your site. Of course, you were careful to modify the configuration file and add fax and fax.our.domain to the $=w class in it. But incoming mail to fax.our.domain is still failing. You run sendmail in rule-testing mode, as above, to verify that the correct entries are in $=w:

here.our.domain
here
[123.45.67.89]
fax                correct
fax.our.domain     correct

Because they are correct, it could be that you made the mistake of changing the configuration file and failing to restart the daemon (Section 1.7.1.2). The following command line fixes the problem (SIGHUP):

# kill -HUP `head -1 /etc/mail/sendmail.pid`