我的电脑是从15年开始使用的，到现在已经3年多的时间了，每次想下载东西，都得删东西，很尴尬。
偶然间看到可以清除Xcode空间，于是我解放了104G的空间。我看到了苹果说可以安全删除，简直就是高兴的不得了。
本来只剩余10个G可用空间，删除掉iOS DeviceSupport文件下的东西，（我的iOS DeviceSupport下从6开始到11.3了，多的不得了）并且清除垃圾桶。瞬间可用空间到了117G。
亲测删除之后不会影响你Xcode运行和真机运行哦。

屏幕快照 2018-04-03 上午11.30.20.png

iOS Dev Nugget 162 Reclaim Disk Space from Xcode Usage

Solid state drives are an awesome performance booster. But unfortunately, they are more expensive and 
naturally come in smaller capacities than hard disk drives. Check these directories Xcode uses and see if you 
can delete some stuff:

    ~/Library/Developer/Xcode/DerivedData/ - It's totally safe to delete directories here. Especially for projects 
that you no longer need. When you rebuild your project, they will be created for you.

    ~/Library/Developer/Xcode/iOS DeviceSupport/ - a folder for each combination of iOS (physical) device 
you have plugged in and the iOS version you were running on it. If you have been doing iOS developer for a 
while, you will have accrued quite a number of these folders that you can remove. They will be re-generated for 
you when you plug in a device if you accidentally delete a more recent folder.

You can easily reclaim a couple of gigs to tens of gigs of space by cleaning up these 2 directories.

首先第一步