gnus: Marking Groups

 
 2.8 Marking Groups
 ==================
 
 If you want to perform some command on several groups, and they appear
 subsequently in the group buffer, you would normally just give a
 numerical prefix to the command.  Most group commands will then do your
 bidding on those groups.
 
    However, if the groups are not in sequential order, you can still
 perform a command on several groups.  You simply mark the groups first
 with the process mark and then execute the command.
 
 ‘#’
 ‘M m’
      Set the mark on the current group (‘gnus-group-mark-group’).
 
 ‘M-#’
 ‘M u’
      Remove the mark from the current group (‘gnus-group-unmark-group’).
 
 ‘M U’
      Remove the mark from all groups (‘gnus-group-unmark-all-groups’).
 
 ‘M w’
      Mark all groups between point and mark (‘gnus-group-mark-region’).
 
 ‘M b’
      Mark all groups in the buffer (‘gnus-group-mark-buffer’).
 
 ‘M r’
      Mark all groups that match some regular expression
      (‘gnus-group-mark-regexp’).
 
    Also SeeProcess/Prefix.
 
    If you want to execute some command on all groups that have been
 marked with the process mark, you can use the ‘M-&’
 (‘gnus-group-universal-argument’) command.  It will prompt you for the
 command to be executed.