Grommish

#!/bin/sh
GPIOCHIP=0
BASE=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/base)
NGPIO=$(cat /sys/class/gpio/gpiochip${GPIOCHIP}/ngpio)
max=$(($BASE+$NGPIO))
gpio=$BASE
while [ $gpio -lt $max ] ; do
        echo $gpio > /sys/class/gpio/export
        [ -d /sys/class/gpio/gpio${gpio} ] && {
                echo out > /sys/class/gpio/gpio$gpio/direction