for dir in /usr/bin /usr/sbin; do
  if test -d "$dir" && ! grep -q -e "^${dir}:" -e ":${dir}:" -e ":${dir}" <<< $PATH; then
    PATH="${dir}:${PATH}"
  fi
done
export PATH

Make sure /usr/bin and /usr/sbin are in PATH
[zsh] Make sure /usr/bin and /usr/sbin are in PATH

These directories are still used on Debian.
