GPIO script to test pins

#!/bin/bash

#num_gpio=$1
read -p "Enter GPIO pin number: " num_gpio

isNumber='^[0-9]+$'
if ! [[ $num_gpio =~ $isNUmber ]] ; then
   echo "error: Not a number" >&2
   num_gpio=199
fi

# active one GPIO pin
echo $num_gpio > /sys/class/gpio/export
# set pin to output signal
echo out > /sys/class/gpio/gpio$num_gpio/direction

# do some things
echo Active GPIO pin $num_gpio
echo 1 > /sys/class/gpio/gpio$num_gpio/value
for i in {1..1}; do echo -e "$i seconds pending\033[A"; sleep 1; done; echo

echo Deactive GPIO pin $num_gpio
echo 0 > /sys/class/gpio/gpio$num_gpio/value
for i in {10..1}; do echo -e "$i seconds pending\033[A"; sleep 1; done; echo

echo Active GPIO pin $num_gpio
echo 1 > /sys/class/gpio/gpio$num_gpio/value
for i in {10..1}; do echo -e "$i seconds pending\033[A"; sleep 1; done; echo

# reset
echo 0 > /sys/class/gpio/gpio$num_gpio/value

# desactive
echo $num_gpio > /sys/class/gpio/unexport