iwevent

iwevent [device]

device
    The device file to monitor (e.g., /dev/input/event0). If no device is specified, iwevent will prompt the user to select a device from the available input devices.

iwevent is a command-line utility in Linux used to display input events generated by input devices such as keyboards, mice, touchpads, and joysticks. It's a debugging tool primarily used by developers and system administrators to monitor raw input events, understand device behavior, and troubleshoot input-related issues.

It provides real-time output of events, showing details like the event type (e.g., key press, mouse movement), event code (specific key or button), and event value (e.g., key state, mouse delta). This information helps in verifying that input devices are working correctly, identifying incorrect configurations, and debugging device drivers. It's invaluable for diagnosing problems where input events aren't being properly recognized or processed by the system.

iwevent requires read access to the input event device files (typically /dev/input/event*). These files are often restricted to root or members of the input group. Running iwevent without proper privileges will result in a permission error.

Each event reported by iwevent contains information about the time the event occurred, the type of event, the code associated with the event, and the value of the event. Understanding the event structure is critical for interpreting the output of iwevent. The format of the event structure can vary depending on the kernel version and the device itself.

If no device is specified, iwevent interacts with the user to allow selection of a device to be monitored. iwevent retrieves information about the input devices registered on the system by reading the device name, vendor ID, product ID and other device properties. iwevent displays these device parameters on the console and ask the user to select one device to monitor.

iwevent is part of the input-utils package, which has been around for many years. It has evolved as the Linux input subsystem has matured, adapting to new input device types and event handling mechanisms. It is often used during development of input drivers and debugging of input handling in graphical environments such as X11 or Wayland.

evtest(1), udev(7)