Try for yourself: temporarily rename usr/lib/libxcrun.dylib within a developer dir like /Library/Developer/CommandLineTools and then try to xcode-select -switch to it. libxcrun.dylib is a hard requirement for a developer dir to be validated, however. The xcrun binary seems to be present in developer directories included with Xcode but not the CLI tools, and it’s also able to query information about SDKs and their included tools. One part of this process is to check whether this path contains usr/lib/libxcrun.dylib, and the xcrun tool, in which case it will invoke xcrun to run the binary.

What’s really going on when we call these shim binaries?īehind the scenes, if I run /usr/bin/git, this shim binary loads functions in libxcselect.dylib that can locate the path to the real binary, depending on how the system has been configured. usr/lib/libxcselect.dylib (compatibility version 1.0.0, current version 1.0.0 ) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1226.10.1 )

Xcode cli