+ This option can be used to print any string instead of the
+ default header line (which depends on the selected mode).
+
+ In user_list mode the header is a format string which allows
+ to include the uid and the user name in the header. See the
+ --format option for more details.
+
+ It is possible to set this to the empty string to suppress
+ the header completely. This is mostly useful to feed the
+ output to scripts.