From mboxrd@z Thu Jan  1 00:00:00 1970
From: dds@aueb.gr (Diomidis Spinellis)
Date: Tue, 3 Jan 2017 22:54:57 +0200
Subject: [TUHS] Pipes in the Third Edition Unix
Message-ID: <d9dd5f1e-f686-c642-5f55-3904946c9489@aueb.gr>

Peter Salus writes "The other innovation present in the Third Edition 
was the pipe" ("A Quarter Century of Unix", p. 50).  Yet, in the 
corresponding sys/ken/sysent.c, the pipe system call seems to be a stump.

         1, &fpe,                        /* 40 = fpe */
         0, &dup,                        /* 41 = dup */
         0, &nosys,                      /* 42 = pipe */
         1, &times,                      /* 43 = times */

On the other hand, the Fourth Edition manual documents the pipe system 
call, the construction of pipelines through the shell, and the use of wc 
as a filter (without an input file, as was required in the Second Edition).

Would it therefore be correct to say that pipes were introduced in the 
Fourth rather than the Third Edition?