# to record
ffmpeg -f v4l2 -i /dev/video0 -c:v libx264 output.mp4
#or
ffmpeg -f v4l2 -i $(find /dev/v4l/by-id/ -name "*AV_TO_USB2.0*" | head -1) -c:v libx264 output.mp4
# to check devices
v4l2-ctl --list-devices