Originally Posted by stever
bash: /dev/ttyACM0: Permission denied
bash: /proc/bus/usb/devices: Permission denied
Are you actually typing "/dev/ttyACM0" at a shell prompt? Then your problem is that you don't know how to use your system through the command line. /dev/ttyACM0 is a device name (for an USB modem), not a shell command or an executable program. /proc/bus/usb/devices is an information listing of connected USB devices, not an executable program. You must give either of those filenames to a program that knows how to do something useful with it, e.g. "cat /proc/bus/usb/devices" to see the contents of /proc/bus/usb/devices.