Rapped

I sat up in bed and rapped my knuckles against the rail to make certain that I was truly awake.

Tom rapped on the table with his knuckles.

Tom rapped on the window.

Tom was sitting in class, lost in daydreams, when the teacher rapped her cane on his desk.

The teacher rapped her cane on the wooden desk, and there was dead silence.

He led me up a flight of stairs, and halted before a door, upon which he gently rapped.