Syntax: copy from-alias-name to-alias-name

    The copy command creates a new alias with the name to-alias-name
    and associates to it the expansion value of the alias with the
    name from-alias-name. A subsequent change to the "from" alias
    will not affect the "to" alias. Any attributes associated with
    the "from" alias will be copied to the "to" alias regardless
    of whether or not an "override on" command has been issued
    previously.

    db> add Postmaster "system@thor.example.com"
    [Entry added to database]
    db> copy Postmaster Postmast
    [1 entry copied]
    db> show Post*
    Key         Value
    ----------  -----------------------------
    postmast    system@thor.example.com
    postmaster  system@thor.example.com
    [2 entries shown]
    db>