The $x macro holds the full name of the sender. When sendmail processes a mail message for delivery, it rewrites the sender's address using the canonify rule set 3 and the parse rule set 0 so that it can determine whether the sender is local. If the sender is local, the parse rule set 0 provides the sender's login name with the $ : operator. Then, if the delivery agent's F=w flag (F=w) is set, [25] the login name is looked up using the method defined by the MailboxDatabase option (MailboxDatabase). [26] If the login name is known, the sender's full name is returned. If necessary, that full name is then processed , throwing away phone numbers and the like and converting the & character. The result, usually fairly close to the sender's actual full name, is the value assigned to the $x macro.
Under certain circumstances, sendmail places a different value in $x :
The $x macro is intended for use in various header definitions. $x is transient. If it is defined in the configuration file or the command line, that definition will be ignored by sendmail . Note that a $& prefix is necessary when you reference this macro in rules (that is, use $&x , not $x ). |