So you've run

$ react-native run-ios

and you got:

Command failed: /usr/libexec/PlistBuddy -c Print:CFBundleIdentifier build/Build/Products/Debug-iphonesimulator/MYAPP.app/Info.plist
Print: Entry, ":CFBundleIdentifier", Does Not Exist

TL;DR

Just stop running that command again and again and try to build the project directly from xcode, you'll grasp more detailed information.

Tip

This is fucking pain in the ass, because it means all and nothing. Simply such error is telling you that your project doesn't build, that's it.

Now you can star reading all the issues related in github and try every stuff you find, sure, and maybe you're lucky and you solve it.

A better approach, would be to stop running that command and trying to build directly the project from xcode, so the error stack is more precise and eventually you can see what's really wrong.

In my case, for some reason, react-native didn't init well, and the third party libraries weren't downloaded and compiled (I missed the third-party folder inside react-naive).

I've solved with the following comment on github, only the second command was different for me:

$ cd node_modules/react-native/scripts && ./ios-install-third-party.sh && cd ../../../
$ cd node_modules/react-native/third-party/glog-0.3.4/ && ../../scripts/ios-configure-glog.sh && cd ../../../../

That's it.