Lesson 13	The Listener Control utility (LSNRCTL)
Objective	Identify the basic listener control functions.

Oracle Listener Control utility (LSNRCTL)

The Listener Control utility (LSNRCTL) within Oracle can perform a host of valuable functions. While the most common commands are start and stop, you can also use the LSNRCTL utility to perform tracing, create pre-spawned listener processes, manage multiple listeners, and lots of other useful functions.
The easiest way to see the commands is to type lsnrctl help .
View the code below to see a sample list of available operations.

dilbert> lsnrctl help

LSNRCTL for IBM/AIX RISC System/6000: Version 2.3.4.0.0 - Production on 11-MAR-4

Copyright (c) Oracle Corporation 1994.  All rights reserved.

The following operations are available
An asterisk (*) denotes a modifier or extended command:

start               stop                status              
services            version             reload              
trace               spawn               dbsnmp_start        
dbsnmp_stop         dbsnmp_status       change_password     
quit                exit                set*                
show*               clbstat             clbserv

One of the most basic commands is lsnrctl stat, which displays the status of the listener process.
Click the View Code link below to see an example.

 dilbert> lsnrctl stat

LSNRCTL for IBM/AIX RISC System/6000: Version 2.3.4.0.0 - Production on 11-MAR-2

Copyright (c) Oracle Corporation 1994.  All rights reserved.

Connecting to (ADDRESS=(PROTOCOL=IPC)(KEY=tom))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for IBM/AIX RISC System/6000: Version 2.3.4.0n
Start Date                02-MAR-99 07:43:15
Uptime                    8 days 23 hr. 26 min. 13 sec
Trace Level               off
Security                  OFF
SNMP                      ON
Listener Parameter File   /etc/listener.ora
Listener Log File         /ora7/home/dba/oracle/product/7.3.4/network/log/listeg
Services Summary...
  tom          has 1 service handler(s)
  jerry        has 1 service handler(s)
The command completed successfully

Remember that if you are using SQL*Net version 1, the utility is called TCPCTL, not LSNRCTL. Fortunately, the utility directives are largely the same. For example, the command to start the SQL*Net version 1 listener is tcpctl start.
Here we see that the listener is working to receive connections for either the TOM or the JERRY database. We also see the location of the listener.ora file, in case we need to make changes.
The next lesson provides additional information about the listener help facility.