On Mon, 2 Sep 2019 09:56:38 -0500, Hans L wrote: > So I ended up running: > $ sudo su > # echo ee1004 0x50 > /sys/bus/i2c/devices/i2c-1/new_device > # echo ee1004 0x51 > /sys/bus/i2c/devices/i2c-1/new_device > # echo ee1004 0x52 > /sys/bus/i2c/devices/i2c-1/new_device > # echo ee1004 0x53 > /sys/bus/i2c/devices/i2c-1/new_device > [Ctrl-D] > > For some reason which I still don't understand, I couldn't just run > each command directly with sudo: > $ sudo echo eeprom 0x50 > /sys/bus/i2c/devices/i2c-1/new_device > bash: /sys/bus/i2c/devices/i2c-1/new_device: Permission denied Can be surprising at first but is easily explained. The shell processes the redirection before executing the command. So it is opening /sys/bus/i2c/devices/i2c-1/new_device as yourself, *then* executes echo as root. What you really want to do is: $ such sh -c "echo ee1004 0x50 > /sys/bus/i2c/devices/i2c-1/new_device" which will force the user change to happen *before* the redirection. -- Jean Delvare SUSE L3 Support
