Minor update to the man page.
@@ -772,8 +772,9 @@ A date and time field matching the
.I time-format
and
.I date-format
-variables. This is used when a timestamp is given instead of the date and time
-being in two separated variables.
+variables. This is used when given a timestamp or the date & time are
+concatenated as a single string (e.g., 1501647332 or 20170801235000) instead of
+the date and time being in two separated variables.
.IP %t
time field matching the
.I time-format
