我上次星期天将我的mac os更新为10.9，但我忘记了命令行工具。
当我检查我的xcode时，我没有找到命令行工具。最后，有人告诉我运行 xcode-select --install 。然后我和他一起工作，而且工作。我安装了命令行工具，一切都很顺利。我的答案可以帮助你

I update my mac os to 10.9 last Sunday,but I forgot command line tools. when I check my xcode,I do not find "command line tools".In the end, some one told me "Run xcode-select --install".Then I fellow him,and it works.I installed "command line tools", everything goes well.hope my answer can help u