The first step in using the listener help utility is to get the list of available commands. This is done by entering lsnrctl help at the UNIX command prompt.
In the previous lesson, you learned how to enter lsnrctl help at the UNIX command to display the list of available commands for the Listener Control utility.

revsp2t> lsnrctl help trace
LSNRCTL for IBM/AIX RISC System/6000: Version 2.3.4.0.0 - Production on 15-MAR-9
9 10:25:36
Copyright (c) Oracle Corporation 1994.  All rights reserved.
trace OFF | USER | ADMIN [<listener_name>] : set tracing to the specified level

For example, suppose you wanted more information about the syntax of the trace command. You would simply enter lsnrctl help trace. Click the View Code button to see an example of what Oracle would return. The output reveals that the commands are lsnrctl trace off, lsnrctl trace user, and lsnrctl trace admin, with an optional listener name for when you're running multiple listeners. The next lesson discusses how to use LSNRCTL to start the listener.