场景
更新 cocoapods 时，使用命令
pod trunk push --allow-warnings
终端抛出了一个错误：
xcrun: error: unable to find utility "simctl", not a developer tool or in PATH ) during validation.
具体一点，就是：
[!] Found podspec `JHRequestDebugView.podspec`
Updating spec repo `master`
CocoaPods 1.6.0.beta.1 is available.
To update use: `sudo gem install cocoapods --pre`
[!] This is a test version we'd love you to try.
For more information, see https://blog.cocoapods.org and the CHANGELOG for this version at https://github.com/CocoaPods/CocoaPods/releases/tag/1.6.0.beta.1
Validating podspec
-> JHRequestDebugView (1.1.0)
- ERROR | [iOS] unknown: Encountered an unknown error (/usr/bin/xcrun simctl list -j devices
xcrun: error: unable to find utility "simctl", not a developer tool or in PATH
) during validation.
[!] The spec did not pass validation, due to 1 error.
解决办法：
参考：https://stackoverflow.com/questions/29108172/xcrun-unable-to-find-simctl
Xcode > Preferences > Locations
Command Line Tools: 这一栏，一开始发现是空的
需要选择一个，就只有一个
这里的版本是：Xcode 9.4 (9F1027a)
重新执行一次命令，OK！
效果：
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🎉 Congrats
🚀 JHRequestDebugView (1.1.0) successfully published
📅 September 28th, 04:03
🌎 https://cocoapods.org/pods/JHRequestDebugView
👍 Tell your friends!
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