Name
M
Synopsis
The M
option is used to set or change a defined
macro’s value. Although this option is allowed in
the sendmail.cf file, it is intended exclusively
for use from the command line. Macros that are defined in the command
line will not override the values of those same
macros defined in the configuration file.
The forms of the M
option are as follows:
OMXvalue← configuration file (old obsolete form) -oMXvalue ← command line (old obsolete form) -MXvalue← command line (V8.7 and later) DXvalue← both are equivalent to this in the configuration and mc files
In all four cases the argument value
is of
type string. The
value
is assigned to the macro named
X
. Pre-V8.7 macro names are always a single
character. Multicharacter macro names that are available with V8.7
are described in Chapter 21 .
One example of the usefulness of this option concerns the
rmail(8) program. Suppose a machine is used for
networked mail. Ordinarily, the $r
macro is given
the value “ESMTP” to signify that
mail is received over the network. But for UUCP mail the
$r
macro should be given the value
“UUCP.” One way to effect such a
change is to arrange for rmail(8) to invoke
sendmail with a command-line argument of:
-oMrUUCP
In this command line, the -o
switch tells
sendmail to define a macro (the
M
) whose name is r
to have the
text UUCP
as its new value.[77] This new value overrides
whatever value $r
might have been given in the
configuration file. The M
option should be approached with caution. If you later ...
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