[tsimionescu]

I understand why it's useful to have access to another process' opened files.

I was wondering more why the Plan9 behavior would be useful - why you would want opening /proc/self/fd/<n> to give you a reference to the same file description instead of giving you a new file description. I assume opening /proc/<other-pid>/fd/<n> doesn't share file descriptions with the other process in Plan9 either, but maybe I'm assuming that wrongly as well.

[kazinator]

If opening the other process' entry shares the description, that means you're messing with its read/write pointer.

[tsimionescu]

I know, which is why I'm hoping that's not the case.

But then, if that's not the case for /proc/<other>/fd/<n>, why would it be for /proc/self/fd/<n> ? Where does this expectation come from?