# Initialize varibles
funtimes=''
username=''

# Setup the function
funtimes_function(){
  # Check if variable set, and if not prompt for input
  if [[ ! $username ]]; then read -p "Username: " username; fi

  # Do stuff
  echo "hello $username"
}

# Usage for the hell of it
usage(){
echo "
  Usage: $0 -a -u <username>
"
}

# Run argument parsing
while getopts ahu: option; do
  case "${option}" in
    a) funtimes=1 ;;
    u) username=${OPTARG};;
    h|*) usage; exit 1;;
  esac
done

if [[ $funtimes ]]; then
  funtimes_function
else
  echo "Where all the white women at ?!"
fi