You don't even need the PID, because /proc/self is a symlink to the /proc/$pid directory provided by the kernel, at least on Linux 2.x. The downside is that neither /proc/self nor /proc/$pid exist on all operating systems. And even on systems where a proc filesystem exists, it is not always mounted. Deleting /proc/$pid/fd/$n will probably just fail with a "permission denied" error, simply because it makes no sense.

Alexander