What does 'one file system' (copy command's -x arguement) mean?
 

cp man page defines -x as --one-file-system : stay on this file system. What does it mean and in what context is it used?

Thanks !

when doing a -Recursive copy, using -x will prevent it from going to /boot or other mounted directories.

Like it will stay on one drive, under on filesystem type and wont traverse partitions, even on the same tree. Maybe , not sure, just guessing.

Try it and find out, what can it hurt?