The $t macro contains the current date and time represented as an integer. The value of $t is set in two places:

• When sendmail first begins to run, it presets several date-oriented macros internally to the date and time it was run. Among those are the $a, $d, $b, and $t macros. This initialization is done after the configuration file is read.

• Each time a new envelope is created, the $d, $b, and $t macros are given a default that is the current time.

$t is intended for use in configuration-file header definitions. $t is transient. If it is defined in the configuration file or in the command line, that definition can be ignored by sendmail. Note that a $& prefix is necessary when you reference this macro in rules (that is, use $&t, not $t).