New code in 2.1.43 (see "get_pipe_inode" in "linux/fs/inode.c") puts
entries for anonymous pipes into the root directory. The 6-digit
number in the filename is the inode of the pipe.
Anonymous pipes are created with the pipe(2) system call. Since
shells typically use anonymous pipes for piped commands (and all sorts
of other programs use them for miscellaneous process/subprocess
communication), there'll usually be a bunch of them sitting around.
If you're interested in finding out who's using these pipes, you can
poke around in the "/proc/*/fd" directories: there'll be links from
file descriptor numbers to the "/.anonymouse-pipe-*" pseudofiles.
Kevin <buhr@stat.wisc.edu>