How to check the status of the listener in Oracle?

To check the status of the Oracle Listener, you can use the following command:

1. Firstly, login to the command line window or terminal on the Oracle database server.
2. Enter the following command in the command line window to check the status of the listener:

lsnrctl status

This command will display the status information of the current listener, including its name, version, listening address, port, protocol, and other details.

1. If the listener is running, it will display something like the following:

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for Linux: Version 12.1.0.2.0 - Production
Start Date                29-NOV-2018 14:41:26
Uptime                    0 days 0 hr. 0 min. 7 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/12.1.0/dbhome_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/diag/tnslsnr/oracle12c/listener/alert/log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=oracle12c)(PORT=1521)))
The listener supports no services
The command completed successfully

1. If the listener is not running, the corresponding error message will be displayed, and troubleshooting and fixing should be done based on the error message.

By following the steps above, you can check the status of the Oracle listener and ensure it is running properly.