How iOS modifies the default Xcode version

The computer loaded two Xcode version, one is Xcode6-beta, one is xcode5.1.1, each time you open the project, the default is to open with Xcode6-beta. Modify open Mode in the introduction also useless, did not come to find the answer in the StackOverflow

After reading on launchservices in OS X I had finally found the solution, thanks for the hint @peter-M.

To modify files Association for certain app one can use lsregister tool. -fso to re-register the app there are parameter, and to unregister -u . Everything can in fact do with just one command:

$ lsregister-f/applications/xcode.app

Or If you want to unregister Xcode 5 and not touch manually set associations earlier:

$ lsregister-u/applications/xcode5-dp5.app

lsregister/System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/LaunchServices.framework/Versions/A/Support/is located in, so add it to your$PATH

Re-login to OS X for changes to apply.

In short, it is in the terminal input:

/system/library/frameworks/coreservices.framework/frameworks/launchservices.framework/support/lsregister-u/ Applications/xcode5.app

Then modify the open mode in the introduction is OK.