Shell Script Invocation Error - Xcode 6
I had the same problem it is solved. One of my pods (in my case was ICETutorial) were casing problems because of its xib files. When I removed this pod the app worked fine. Also you may need to uninstall pods and install them again; also update them for iOS8 support.
Try to check each pod in your app; I guess one of them casing this problem.
Hope this will help you.
Thanks
I had the same error and I found that carthage was not installed. Installed carthage through brew then did a rebuild. This time got a message to setup Fabric because it was used by the original developer. Installed Fabric and followed their instructions. The problem is gone. Hope this helps.
Solution - This error was caused by the new version of Xcode (6), trying to convert xibs and used in some of the pods used in the project.
Solution 1 - Re-download Xcode 5.1 from the member centre: https://developer.apple.com/downloads/index.action
Solution 2 - Update Pods, linked files and current code base to meet iOS 8 standards.