+ echo 4
    + echo out
    script1.sh: line 13: /sys/class/gpio/gpio4/direction: Permission denied
    + echo 7
    + echo in
    script1.sh: line 17: /sys/class/gpio/gpio7/direction: Permission denied
    + echo 1
    script1.sh: line 20: /sys/class/gpio/gpio4/value: Permission denied
    + cat /sys/class/gpio/gpio7/value
    1
    + echo 4
    + echo 7