Most NCL commands accept two types of prepositional phrases:

    o  Use "by" phrase to specify an access control string for remote
       system management.

    o  Use "with" phrase to limit the action of an NCL command to
       those entities that match the qualifying condition.

    You can specify one or both prepositional phrases in any NCL
    command that accepts them. Separate the prepositional phrases by
    a comma.

1  –  By Preposition

    The "by" prepositional phrase authenticates that an account or
    proxy account for a particular user has been set up with the
    proper access control information. Use of the by preposition
    is portable to other DECnet-Plus systems. Use the following
    format to append access control information using the by
    preposition.

       by user=username, password=password, account=account, -
         proxy={TRUE/FALSE}

    For Tru64 UNIX, NCL ignores any use of the by proxy clause
    so that the modifier "by proxy=true" (i.e., proxy access
    allowed) is always in effect.

    If user j_smith has privileges to access the session control
    application graphics_exchange on the remote node, he can use
    the by preposition as follows:

    ncl> ! On node .admin.finance
    ncl> show node .admin.artists session control application -
    _ncl> graphics_exchange all counters, by user=j_smith, -
    _ncl> password=DoNotUse
          .
          .
          .

    For Tru64 UNIX, access control does not have any effect when the
    NCL command is directed to the local node. This happens because
    NCL uses interprocess communication instead of DECnet-Plus to
    communicate with node 0, the local node, and therefore the user's
    privileges are determined by the user id that NCL is running under.

2  –  With Preposition

    Use the "with" prepositional phrase to qualify an NCL command to
    limit the scope of its operation. Also called filtering, this
    process is useful in displaying or acting upon only certain
    information. The expression supplied as part of the with clause
    must be an attribute of the entity (or entities) specified in the
    command.

    ncl> show session control application *, with maximum instances>0

    For every session control application entity on node 0 (the local
    system), NCL finds the entities with maximum instances greater
    than zero, and returns the identifying information about those
    session control application entities.

    The with prepositional phrase is a boolean expression that can
    use the relational operators as follows:

    Symbol   Meaning

    <>       Not equals
    <        Less than
    <=       Less than or equal to
    >        Greater than
    >=       Greater than or equal to

2.1  –  Restrictions of With Clause

    It is possible (but not improbable) for the value of an
    attribute to change between the time that the attribute
    value is tested against the with clause value and the time
    that the directive is actually issued to the entity. This
    limitation can lead to cases such as the following:

    ncl> show 0 session control port *, with send queue > 0

    Node 0 Session Control Port %XCC354000
    AT 1994-11-13-16:32:03.249-05:00I0.269

    Status

       Send Queue = 0

    In this case, the attribute briefly goes non-zero, then
    immediately returns to zero again. Unfortunately, the
    attribute changed value between the time that it was
    sampled by the entity filtering software in the CML (CMIP
    Management Listener) and the time that the Show directive
    was issued to that entity instance. This is generally
    not a problem. Most attributes are stable enough that this
    rarely happens.