Re: [bug-grep] [patch] getting '--devices=skip' to work

[Paul Eggert]

It's probably worth mentioning that POSIX does not allow "grep" to use
O_NONBLOCK when "grep" is invoked in the standard way on a text file.
It must use O_RDONLY only.  Here's the chapter and verse:

http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap01.html#tag_01_07_01_07

Come to think of it, coreutils "dd" violates this part of the
standard; it always uses O_NOCREAT.  I'll submit a patch for that.
Also, I think both "dd" and "touch" use nonstandard flags when
writing; I'll see if I can fix that too.  I'm not 100% sure about
"tail -f"'s use so perhaps we should leave sleeping dogs lie.