root@localhost:/sys/class/gpio/gpio464# ls
active_low device direction edge power subsystem uevent value
root@localhost:/sys/class/gpio/gpio464# cat value
0
root@localhost:/sys/class/gpio/gpio464# echo 1 >value
-bash: echo: write error: Operation not permitted
root@localhost:/sys/class/gpio/gpio464# echo out >direction
root@localhost:/sys/class/gpio/gpio464#
root@localhost:/sys/class/gpio/gpio464#
root@localhost:/sys/class/gpio/gpio464# cat value
0
root@localhost:/sys/class/gpio/gpio464# echo 1 >value
root@localhost:/sys/class/gpio/gpio464# cat value
0