#!/bin/bash
# http://www.codelibary.com/Bash/Arrow-key-detect.html

arrowup='\[A'

SUCCESS=0
OTHER=65

echo -n "Press a key...  "
# May need to also press ENTER if a key not listed above pressed.
read -n3 key                      # Read 3 characters.

echo -n "$key" | grep "$arrowup"  #Check if character code detected.
if [ "$?" -eq $SUCCESS ]
then
  echo "Up-arrow key pressed."
  exit $SUCCESS
fi

exit $OTHER