I'd like to simply watch all devices added and removed from my system and view their USB vendor ID, product ID and revision and other relevant information. How can I do this in Linux? Is there a logfile that I can tail -f or does this require something else?

  • Is dmesg detailed enough? May 2, 2013 at 0:32
  • I don't see any output from tailing /var/log/dmesg. Plug in/remove = nothing. May 2, 2013 at 0:38
  • 1
    @RanyAlbegWein dmesg does not display all USB events, only ones for which a handler exists and calls printk().
    – Chris Down
    May 2, 2013 at 0:42
  • So is there a way to tail udev for the information? May 2, 2013 at 0:43

3 Answers 3


You can do that with udevadm:

udevadm monitor --subsystem-match=usb --property


udevadm monitor --subsystem-match=usb --property --udev

to filter only udev events. If you want to grep for a particular property you will have to un-buffer udevadm output (with tools like stdbuf, script, unbuffer...):

stdbuf -i 0 -o 0 -e 0 udevadm monitor --subsystem-match=usb --property --udev | grep DEVPATH


script -q /dev/null -c "udevadm monitor --subsystem-match=usb --property --udev" | grep PRODUCT


unbuffer udevadm monitor --subsystem-match=usb --property --udev | grep -E 'ID_VENDOR_ID|ID_MODEL_ID'

This information appears in the kernel logs — typically in /var/log/kern.log, or /var/log/syslog, or some other file (it depends on your syslog configuration, different distributions have different defaults).

If you'd like something pre-filtered, you can add an udev rule. Create a file /etc/udev/rules.d/tkk-log-usb.rules containing something like:

SUBSYSTEM=="usb", RUN+="/usr/local/sbin/tkk-usb-event"

The environment of the program is populated with a lot of variables describing the device, including:

  • ACTION (add or remove)
  • DEVICE is a path to the device if you want to access it
  • ID_MODEL_ID and ID_VENDOR_ID contain the model and vendor ID, and ID_MODEL and ID_VENDOR contain the corresponding text
  • ID_SERIAL contains the serial number of the device (if available)

If you just want to monitor the current plugged USB devices watch --no-title lsusb could fit the bill.

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