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
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.