Is there a device file that just blocks?

Question

... something similar to /dev/null, but that just blocks all bytes that are written to it?

What I need is a trick to hold an arbitrary executable in memory by blocking its output. Pipes don't seem to be usable, because the output gets written to a buffer first.

Answer 1

You can create a named pipe (fifo) using mkfifo. Writes to this type of special file will block until a process reads from it.

$ mkfifo blocker
$ echo hello > blocker # "hangs"

In another session:

$ cat blocker
hello                  # the `echo` above unblocks after this