root@Taomon:/home/alex# udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[11208.663450] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2 (usb)
KERNEL[11208.666363] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0 (usb)
KERNEL[11208.687840] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003 (hid)
KERNEL[11208.692357] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26 (input)
KERNEL[11208.692719] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26/event18 (input)
KERNEL[11208.692965] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26/js1 (input)
KERNEL[11208.693166] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/hidraw/hidraw1 (hidraw)
UDEV  [11208.717776] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2 (usb)
UDEV  [11208.718901] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0 (usb)
UDEV  [11208.719674] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003 (hid)
UDEV  [11208.720999] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26 (input)
UDEV  [11208.721034] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/hidraw/hidraw1 (hidraw)
UDEV  [11208.722728] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26/event18 (input)
UDEV  [11208.726981] add      /devices/pci0000:00/0000:00:1a.1/usb2/2-2/2-2:1.0/0003:11FF:3341.0003/input/input26/js1 (input)

root@Taomon:/home/alex# udevadm test-builtin input_id /sys/class/input/js0
calling: test-builtin
load module index
Network interface NamePolicy= disabled on kernel commandline, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 9
capabilities/ev decoded bit map:
  bit    0: 0000000000000009
capabilities/abs raw kernel attribute: 7
capabilities/abs decoded bit map:
  bit    0: 0000000000000007
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: 0
capabilities/key decoded bit map:
ID_INPUT_ACCELEROMETER=1
test_key: no EV_KEY capability
unload module index
Unloaded link configuration context.

root@Taomon:/home/alex# udevadm test-builtin input_id /sys/class/input/js1
calling: test-builtin
load module index
Network interface NamePolicy= disabled on kernel commandline, ignoring.
timestamp of '/etc/systemd/network' changed
timestamp of '/lib/systemd/network' changed
Parsed configuration file /lib/systemd/network/99-default.link
Created link configuration context.
ID_INPUT=1
capabilities/ev raw kernel attribute: 1b
capabilities/ev decoded bit map:
  bit    0: 000000000000001B
capabilities/abs raw kernel attribute: 30027
capabilities/abs decoded bit map:
  bit    0: 0000000000030027
capabilities/rel raw kernel attribute: 0
capabilities/rel decoded bit map:
capabilities/key raw kernel attribute: fff00000000 0 0 0 0
capabilities/key decoded bit map:
  bit    0: 0000000000000000
  bit   64: 0000000000000000
  bit  128: 0000000000000000
  bit  192: 0000000000000000
  bit  256: 00000FFF00000000
ID_INPUT_JOYSTICK=1
test_key: checking bit block 0 for any keys; found=0
test_key: checking bit block 64 for any keys; found=0
test_key: checking bit block 128 for any keys; found=0
test_key: checking bit block 192 for any keys; found=0
unload module index
Unloaded link configuration context.