Cannot find Arduino under /dev Directory I have the Arduino board connected to a USB port of my machine. But I cannot find it under /dev/ directory in my Ubuntu. Does anyone know how to deal with this issue? By the way, "lsusb"'s output proves that it has been recognized. Here is the output of this command:

Bus 002 Device 002: ID 8087:8000 Intel Corp. 
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 007: ID 413c:2105 Dell Computer Corp. Model L100 Keyboard
Bus 003 Device 013: ID 2341:0043 Arduino SA Uno R3 (CDC ACM)
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub


Here is the output of ls -l /dev/ttyACM*

ls: cannot access /dev/ttyACM*: No such file or directory


and the dmesg output when disconnect and reconnect the device:

[1653809.002715] usb 3-11: USB disconnect, device number 13
[1653832.188835] usb 3-11: new full-speed USB device number 14 using xhci_hcd
[1653832.211392] usb 3-11: New USB device found, idVendor=2341, idProduct=0043
[1653832.218400] usb 3-11: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[1653832.226003] usb 3-11: Manufacturer: Arduino (www.arduino.cc)
[1653832.231859] usb 3-11: SerialNumber: 85235353137351708191
[1653832.237468] usb 3-11: ep 0x82 - rounding interval to 1024 microframes, ep desc says 2040 microframes
Note that lsusb does not guarantee the drives are loaded (See https://superuser.com/questions/165733/will-lsusb-and-lspci-list-devices-for-which-the-system-has-no-drivers) 

Per the https://stackoverflow.com/a/14586884/1653571 answer, try an 'lsmod' and see whether you have a 'cdc_acm' module loaded.