I upgraded my Mac to 10.10.3 and Xcode to 6.3.1 yesterday; today I can\'t use git, codesign_allocate....and more.
`sh: line 1: 18421 Abort trap:
Sometimes issue is with path of Xcode's command line tool which could be fixed by fixing path of XCode. Please check path of XCode with command xcode-select -p. If it shows incorrect XCode path then you can use command sudo xcode-select -s PATH_TO_XCODE_DEVELOPER_FOLDER.
For example, sudo xcode-select -s "/Application/XCode.app/Contents/Developer"