Bash: Get directory current script is located in (with Bash 2 fallback)

gistfile1.sh

#!/usr/bin/env bash

SCRIPT_PATH="${BASH_SOURCE[0]}"                             # for Bash > 3.0
[ -z "${SCRIPT_PATH}" ] && SCRIPT_PATH=$(readlink -f "$0")  # for Bash 2
SCRIPT_DIR=$(cd $(dirname "${SCRIPT_PATH}") && pwd)

echo "Script path:      ${SCRIPT_PATH}"
echo "Script directory: ${SCRIPT_DIR}"