The LSNRCTL help utility is a built-in reference for Oracle Database administrators. It provides syntax, options, and short descriptions for every available Listener Control command—without the need to open separate documentation. This is especially useful during troubleshooting or when working in restricted environments where internet access is limited.

To display the complete list of LSNRCTL commands:

lsnrctl help

Sample output in Oracle 23ai:

LSNRCTL for Linux: Version 23.4.0.0.0 - Production

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

start               stop                status
services            version             reload
save_config         trace               spawn
change_password     set*                show*
quit                exit

From this list, you can choose any command and get more details about its usage.

To see detailed syntax for a single command, run:

lsnrctl help <command_name>

Example: Checking the syntax for the trace command:

lsnrctl help trace

Sample output:

trace OFF | USER | ADMIN [] : 
Set tracing to the specified level.

The trace command enables listener tracing for diagnostic purposes:

• OFF – Disables listener tracing (default).
• USER – Enables basic tracing for connection activity.
• ADMIN – Enables detailed tracing, typically for Oracle Support troubleshooting.

If multiple listeners are running, specify the listener name:

lsnrctl trace ADMIN LISTENER2

lsnrctl help is useful when:

• Verifying the correct syntax before executing a command on a production system.
• Learning rarely used LSNRCTL options without leaving the command line.
• Quickly recalling commands for managing multiple listeners.

For example, before restarting a listener with reload, you can confirm the syntax:

lsnrctl help reload

In practice, lsnrctl help complements all other LSNRCTL commands discussed in Lesson 13. It serves as your on-demand guide while working with operations like start, stop, status, services, and change_password.

Whether used as a quick tip or part of a larger workflow, the LSNRCTL help utility is an essential time-saver for Oracle DBAs. By keeping syntax and usage examples immediately accessible, it supports efficient listener management in Oracle 19c and 23ai environments.