The following conventions are used in the command descriptions:

   - Words presented in upper case are keywords that must be entered
     as shown.  These can be entered using either upper or lower case,
     and can generally be abbreviated to three characters.

   - Words presented in lower case represent values to be determined
     by the user (node names for example).

   - Words or phrases enclosed in square brackets ("[xxx]") are optional.
     If these are not supplied, some default value or action is assumed.