sudo xcode-select -s /Applications/Xcode 10.app/Contents/Developer

languoguangs-iMac:/ languoguang$ sudo xcode-select -s /Applications/Xcode 10.app/Contents/Developer
xcode-select: error: invalid argument '10.app/Contents/Developer'
Usage: xcode-select [options]

Print or change the path to the active developer directory. This directory
controls which tools are used for the Xcode command line tools (for example, 
xcodebuild) as well as the BSD development commands (such as cc and make).

Options:
  -h, --help                  print this help message and exit
  -p, --print-path            print the path of the active developer directory
  -s <path>, --switch <path>  set the path for the active developer directory
  --install                   open a dialog for installation of the command line developer tools
  -v, --version               print the xcode-select version
  -r, --reset                 reset to the default command line tools path
languoguangs-iMac:/ languoguang$ sudo xcode-select -s "/Applications/Xcode 10.app/Contents/Developer"

因为我在应用程序中的Xcode名称是Xcode 10，

sudo xcode-select -s "/Applications/Xcode 10.app/Contents/Developer"

的工作原理。

没有Xcode:创建文件/usr/local/bin/xcodebuild的内容来欺骗XcodeSelect

  #!/bin/bash
  exit 0

Chmod +x /usr/local/bin/xcodebuild

以防你使用xcode beta版:

sudo xcode-select -s /Applications/Xcode-Beta.app/Contents/Developer

我无需安装完整的Xcode应用程序就可以解决这个错误。但是，你必须安装xcode命令行工具。

从这里开始:

$ CD /usr/bin $ sudo mv xcodebuild xcodebuild。orig(以防万一的备份) $ vim xcodebuild 粘贴如下内容:

#!/bin/bash
if [[ $1 == '-version' ]]; then
  echo "Xcode 10.2.1"
  echo "Build version 10E1001"
else
  /usr/bin/xcodebuild.bak $@
fi

$sudo chmod +x xcodebuild

只需运行sudo xcode-select -r即可自动重置路径。

 -r, --reset
              Unsets any user-specified developer directory, so that the developer directory will be found via the default search mechanism. This command must  be
              run with superuser permissions (see sudo(8)), and will affect all users on the system.

以上这些方法对我都没用。我最初单独安装了命令行工具，然后是所有的Xcode。对我有用的是卸载如下所示的命令行工具。然后，当再次尝试运行xcode-select时，我被要求重新安装它们。

*顺便说一下，我发现这个线程的原因是因为我用macports安装了一些库(特别是gcc)，大概是用旧的命令行工具，然后我在开发中途安装了完整的Xcode。所以无论如何，对于我的情况，我必须在删除独立的命令行工具后重新安装macports，重新安装它们，重新安装gcc，然后我的编译工作。