$&
Delay macro expansion until runtime LHS and RHS operator
Normally, sendmail macros are
expanded (replaced with their values) when the
configuration file is read. For those situations
when a sendmail macro should
not be expanded, but rather should be used in rules
as is, V8 sendmail offers the
$& prefix.
For example, consider the following RHS of a
rule:
R... $w.$&M
Normally, when sendmail
encounters this RHS in the configuration file, it
will recursively expand $w into its final text value (where
that text value is your hostname, such as
wash.dc.gov). But because the
M
sendmail macro is prefixed
(here, with $&), it is not expanded until the
rule is processed.
The $& operator
can be used in either the LHS or the RHS of a rule.
The $&
operator is described in full in Use Value As Is with $& on page
793.
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