How to use CMake to get command line output as an argument?

I'm using CMake to build linux module mode, so I'm retrieving header files on ubuntu, currently I'm running ubuntu in docker and it has:

/lib/modules/4.15.0-76-generic

Well, several days later if I build a new image, it will become updated value:

/lib/modules/4.15.0-78-generic

So this number is changing, but there's only one directory under /lib/module, and it's not 'uname -a' output.

Linux 0a08e87c0a18 4.15.0-50-generic

So I wish to know if there's a convenient way in CMake just like shell ls /lib/module, and then I can use command line output as a parameter for header/library root directory?

Thanks a lot.