[1amzave]

Sure -- but my point was merely in regard to the (mis)use of the word "pure" here. Avoiding calling out to external executables and remaining purely within the shell itself is also frequently a good way to improve performance (sometimes quite dramatically), so being aware of the difference is worthwhile.

(Also, /dev/tcp isn't a filesystem, just a simulation of one constructed purely within bash itself, so it wouldn't in fact depend on anything but the relevant networking syscalls.)