external:ubuntu-core-16-arm-32 .../tests/main/security-device-cgroups-serial-port# udevadm info /dev/ttyS4
Unknown device, --name=, --path=, or absolute path in /dev/ or /sys expected.
external:ubuntu-core-16-arm-32 .../tests/main/security-device-cgroups-serial-port# udevadm info --path=/dev/ttyS4
syspath not found
external:ubuntu-core-16-arm-32 .../tests/main/security-device-cgroups-serial-port# ls -al /dev/ttyS
ttyS0         ttyS4         ttyS4.spread  ttyS5         
external:ubuntu-core-16-arm-32 .../tests/main/security-device-cgroups-serial-port# ls -al /dev/ttyS4
crw-r--r-- 1 root root 4, 68 Dec  6 13:51 /dev/ttyS4