PATH="${PATH:-/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games}"
for dir in \
    "/usr/games" \
    "/usr/sbin" \
    "/sbin" \
    "${HOME}/.cabal/bin" \
    "${HOME}/.cargo/bin" \
    "${HOME}/bin"; do
    case :$PATH: in
        *:${dir}:*)
             # ${dir} already in PATH
            ;;
        *)
            PATH="${dir}:${PATH}";;
    esac
done