message: DOWNLOAD -> DOWNLOAD_DIR
diff: # limitations under the License.
  readonly VERSION='v0.7.1'
  -readonly DOWNLOAD='download'
  # The relative location of this script.
  -dir="$(dirname "$0")/${DOWNLOAD}"
  -readonly dir
  +DOWNLOAD_DIR="$(dirname "$0")/download"
  +readonly DOWNLOAD_DIR
  declare file="shellcheck-${VERSION}" # Name of the file to download
  -declare cmd="${dir}/shellcheck-${VERSION}" # Path to the executable
  +declare cmd="${DOWNLOAD_DIR}/shellcheck-${VERSION}" # Path to the executable
  case "$(uname -s)" in
  Linux) file+='.linux.x86_64.tar.xz'; cmd+='/shellcheck';;
  Darwin) file+='.darwin.x86_64.tar.xz'; cmd+='/shellcheck';;
  @@ -31,12 +30,12 @@ esac
  readonly file cmd
  if [[ ! -s "${cmd}" ]]; then
  - mkdir -p "${dir}"
  + mkdir -p "${DOWNLOAD_DIR}"
  readonly url="https://github.com/koalaman/shellcheck/releases/download/${VERSION}/${file}"
  - curl --location --fail --output "${dir}/${file}" "${url}"
  + curl --location --fail --output "${DOWNLOAD_DIR}/${file}" "${url}"
  - pushd "${dir}"
  + pushd "${DOWNLOAD_DIR}"
  sha256sum --check --ignore-missing ../hashes.sha256
  if [[ "${file}" == *'.tar.xz' ]]; then
  tar xf "${file}"
  