syscall.Exec replaces the current process with the one invoked.
If you want to run an external command while keeping the original program running, you need to use exec.Command
By the way, the link you included does say:
Sometimes we just want to completely replace the current Go process with another (perhaps non-Go) one.
If you really want to use the
syscall package, you can use
syscall.StartProcess which does a fork/exec as opposed to a plain exec.