xev

TLDR

Start xev

$ xev

Show specific event types

$ xev -event [keyboard]

Monitor specific window

$ xev -id [window_id]

Use root window

$ xev -root

Show only key events

$ xev -event keyboard

SYNOPSIS

xev [-event type] [-id window] [-root] [options]

xev displays X11 events. It shows what the X server receives.
Window opens to capture events. Click, type, move mouse.
Event details are printed. Keycodes, coordinates, modifiers.
Useful for debugging input. Find keycodes for configuration.
Window ID mode monitors other windows. Spy on specific applications.
Root mode catches global events. Display-wide monitoring.

PARAMETERS

-event TYPE

Event type filter.

-id WINDOW

Window ID.

-root

Root window.

-name NAME

Window name.

-geometry GEOM

Window geometry.

EVENT TYPES

keyboard - Key events
mouse - Pointer events
button - Button events
motion - Motion events
expose - Expose events

CAVEATS

X11 only, not Wayland. Creates visible window. Output is verbose.

HISTORY

xev is part of the standard X11 utilities. It's essential for understanding X input events and configuring key bindings.

xev