It is possible to hide part or all of a list header (except for the list title) from users who send the REVIEW command or who try to view the list's configuration via the CataList. The following syntax is used:

* My very own list
* blah blah blah
* This line is hidden
* This line is also hidden
* This line is not hidden

The sequence can be repeated as many times as required. GET will return the unedited header with the .HH sequences, REVIEW will replace hidden lines with a note saying that lines were hidden. You can't hide the fact that some lines were hidden because it would lead to people spending hours trying to figure out problems which only appear to be problems because some of the keywords are not visible. Please note that L-Soft will not field support inquiries with hidden headers; you must send the entire raw header (including the .HH lines) when requesting support.

Also note the following:

      • .HH commands can be nested.
      • The .HH ON and .HH OFF dot commands are respected in KEYWORDS files called from list headers with the .IK dot command.  Previous versions ignored .HH commands in KEYWORDS files.
      • In a KEYWORDS file, .HH OFF found in excess of .HH ON will be ignored.  This ensures that a KEYWORDS file called from inside of an .HH ON block will not expose the remainder of that block upon return from the call.
      • Similarly, LISTSERV will internally generate as many .HH OFF tags as necessary before exiting the KEYWORDS file and returning to the list, if more .HH OFF tags than .HH ON tags exist in the KEYWORDS file.

The last two precautions ensure that .HH coding errors in a KEYWORDS file will not result in exposure of keyword settings that it is desired to keep hidden.