install_xcode_cli_tools.sh

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

is_xcode_cli_tools_installed() {
  xcode-select -p >/dev/null 2>&1
  [[ $? -eq 0 ]]
}

install_xcode_cli_tools() {
  local flag='/tmp/.com.apple.dt.CommandLineTools.installondemand.in-progress'
  touch $flag

  local UPDATE_NAME=$( softwareupdate --list \
    | grep '\*.*Command Line' \
    | head -n 1 \
    | awk -F"*" '{print $2}' \
    | sed -e 's/^ *//' \
    | tr -d '\n'
  )

  softwareupdate --install --verbose "${UPDATE_NAME}"
  local success=$?

  rm $flag

  return $success
}

main() {
  is_xcode_cli_tools_installed || install_xcode_cli_tools
}

main