sendmail, 4th Edition

Macros in Rule Set Names

Macros can be used in any or all of a part of a rule set declaration. They can be used to declare a name:

D{NAME}myname
S${NAME}

or to declare a number:

D{NUMBER}12
S${NUMBER}

or both a name and a number:

D{NAME}myname
D{NUMBER}12
S${NAME}=${NUMBER}

or even the whole thing:

D{SET}myset=12
S${SET}

You can use single- and multicharacter sendmail macros in any combination. Macros can be used in any rule set declaration, including subroutine calls inside rules:

R $* < $=w > $*       $@ $>${NAME} $2

But they cannot be used in the S= or the R= of delivery agents:

Mprog, P=sh, ..., S=$X, R=$X, ...
                    ↑     ↑
                    neither of these will work

Macros can be used in the command line to modify a configuration file when sendmail is run. Consider the desire to call one rule set when running as a daemon and another when processing the queue. You might declare such rules like this:

R $*            $: $&A
R daemon        $@ $>Daemon_ruleset
R queue         $@ $>Queue_ruleset
R $*            $@ $>UndefinedA_ruleset

The two different runs might look like this:

# /usr/sbin/sendmail -MAdaemon -bd
# /usr/sbin/sendmail -MAqueue -q30m

The first defines the $A sendmail macro to have the value daemon and results in this subroutine call:

R daemon        $@ $>Daemon_ruleset

The second defines the $A sendmail macro to have the value queue and results in this different subroutine call:

R queue         $@ $>Queue_ruleset

Note that any different or missing command-line setting for $A will result in the fallback subroutine call:

R $*            $@ $>UndefinedA_ruleset

Also note that you can ...