Have you upgraded to OS X El Cap­i­tan from App Store?

Have you sud­denly started get­ting the fol­low­ing error in your project?

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

If yes, then here is the solution

xcode-select --install

Remem­ber, in MAC git is attached to XCode’s Com­mand line tools.
摘自：http://tips.tutorialhorizon.com/2015/10/01/xcrun-error-invalid-active-developer-path-library-developer-commandline-tools-missing-xcrun/