#!/bin/sh
G1=18
G2=33

SYS=/sys/class/gpio

[ -d $SYS/gpio$G1 ] || echo $G1 > $SYS/export
[ -d $SYS/gpio$G2 ] || echo $G2 > $SYS/export

echo in > $SYS/gpio$G1/direction
echo out > $SYS/gpio$G2/direction

echo 1 > $SYS/gpio$G2/value
[ "$(cat $SYS/gpio$G1/value)" = "1" ] || echo "1 failed"

echo 0 > $SYS/gpio$G2/value
[ "$(cat $SYS/gpio$G1/value)" = "0" ] || echo "0 failed"

echo $G1 > $SYS/unexport
echo $G2 > $SYS/unexport