Subject: bug#36455: Question on reading from socket(pair) instead from pipe

From: Paul Eggert <[email-masked]>
Date: Mon, 1 Jul 2019 01:17:41 -0700

Dr. Werner Fink wrote:
> IMHO reading data from a FIFO/pipe or from a FSOCK/socket(pair) should result
> in the same result.

Yes it should, but only if you invoke 'grep' with the same arguments both times, 
which I expect you didn't. Look at the two execve lines in the strace output.