hands-off macOS command-line-tools install

setup_clt.sh

if [[ $(/usr/bin/xcode-select -p &>/dev/null; /bin/echo $?) == 2 ]]; then
  cmd_line_tools_temp_file="/tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress"
  touch "$cmd_line_tools_temp_file"
  cmd_line_tools=$(softwareupdate -l | awk '/\*\ Command Line Tools/ { $1=$1;print }' | tail -1 | sed 's/^[[ \t]]*//;s/[[ \t]]*$//;s/*//' | cut -c 2-)
  softwareupdate -i "$cmd_line_tools" --verbose
  if [[ $(/usr/bin/xcode-select -p &>/dev/null; /bin/echo $?) != 2 ]]; then
    echo "CLT installed."
    if [[ -f "$cmd_line_tools_temp_file" ]]; then
      rm "$cmd_line_tools_temp_file"
    fi
  else
    die "CLT install failed"
  fi
fi