wdctl:tldr:087f8

The "wdctl" command is used to interact with and control the watchdog timer on a Linux system.

A watchdog timer is a hardware or software component that monitors the functioning of a system. It is typically used to automatically restart the system if it becomes unresponsive or hangs. The watchdog timer expects to be "fed" periodically by a specific process or daemon. If the watchdog timer does not receive the expected signal within a certain timeframe, it assumes that the system is no longer functional and initiates a system reset.

The "wdctl" command provides a way to query the status of the watchdog timer and control its settings. When executed with appropriate options, "wdctl" allows you to:

1. View the current status: You can check if the watchdog timer is enabled or disabled, and verify the timeout settings (the time interval within which the watchdog timer expects to receive the "feed" signal).

2. Enable or disable the watchdog: You can turn the watchdog timer on or off. If enabled, it starts monitoring the system for possible hangs.

3. Feed the watchdog timer: When the watchdog is enabled, you need to periodically feed it with a specific signal to prevent the system from being reset. This signal can be sent manually using the "wdctl" command.

4. Change the timeout value: You can adjust the timeout value, i.e., the amount of time the watchdog timer allows for the "feed" signal before it assumes a system hang and triggers a reset.

The exact functionality and available options of "wdctl" may vary slightly depending on the Linux distribution and specific watchdog timer implementation being used. It is usually executed from the command line with appropriate options to manage the watchdog functionality.