I believe the author is using that as an example of a command that will 'wedge' if you tried to kill -9 it. The rest of it is an example of how to dump the cau

I believe the author is using that as an example of a command that will 'wedge' if you tried to kill -9 it. The rest of it is an example of how to dump the cause of a process that is wedged. "/proc/{pid}/wchan" contains the name of the current syscall a process is executing. Basically you should be able to use everything but the first line of that section as a shell script(with some modifications) to determine the cause of a wedged process.