Nov 8, 2018

List of messages ( msglist) of mailx

Many  commands take an optional list of messages ( msglist) on which to
       operate, which defaults to the current message. A msglist is a list  of
       message specifications separated by <blank>s, which can include:

       n      Message number n.

       +      The  next undeleted message, or the next deleted message for the
       undelete command.

       -      The next previous  undeleted  message,  or  the next  previous
       deleted message for the undelete command.

       .      The current message.

       ^      The  first  undeleted  message, or the first deleted message for
       the undelete command.

       $      The last message.

       *      All messages.

       n-m    An inclusive range of message numbers.

       address
       All messages from address; any address as shown in a header summary shall be matchable in this form.

       /string
       All messages with string in the subject line (case ignored).

       :c     All messages of type c, where c shall be one of:

       d
       Deleted messages.

       n
       New messages.

       o
       Old messages (any not in state read or new).

       r
       Read messages.

       u
       Unread messages.