From: steffen@sdaoden.eu (Steffen Nurpmeso)
Subject: [TUHS] Bourne shell and comments
Date: Thu, 20 Apr 2017 00:07:28 +0200 [thread overview]
Message-ID: <20170419220728.H4VbN%steffen@sdaoden.eu> (raw)
In-Reply-To: <20170419210224.GA701493@lisa.in-ulm.de>
Sven Mascheck <mascheck at in-ulm.de> wrote:
|On Wed, Apr 19, 2017 at 06:48:34AM +1000, Warren Toomey wrote:
|> I was trying to configure C news on 2.9BSD today and I found that its
|> Bourne shell doesn't grok # comments. The Bourne shell in 2.11BSD does.
|>
|> So I thought: when did the Bourne (and other) shells first grok # as
|> indicating a comment? Was this in response to #! being added to the
|> kernel, or was it the other way around? And was the choice of #!
|> arbitrary, or was it borrowed from somewhere else?
|>
|> Datum point: 2.9BSD's kernel can recognise #!, but the sh can't recognise \
|> #.
|
|Dennis' email about #! to Berkeley is dated Jan 10 '80.
|I've never seen any hint, how the bang in #! was chosen. Looks racy \
|at least..
|#! on BSDs was available as compile time option in 4.0BSD (~Oct '80?)
|and default on 4.2BSD (~Sep '83).
|BTW, AFAIK, the #! implementation in 2.8BSD (compile time option) is not
|from research but seems to come from U.S. Geological Survey, Menlo Park.
|
|The BSD csh hack in sh&csh (# special as first character in a file, \
|service.c),
|came with 3BSD, also in '80.
|
|I found # as comment character in the BSD-sh first in CSRG 4.1.snap
|(~Apr '81, word.c). And at Bell Labs, as mentioned, it came with SysIII, \
|also ~81.
|BTW, 4.3BSD ('86), and thus 2.10 BSD, brought an interesting change:
|# is only recognized in non-interactive mode. In interactive mode
|you actually get this:
| $ # echo x
| #: not found
|This was not changed in 4BSD until sh was replaced by ash in 4.3 Net/2.
Hmm. Kurt Shoens added # as a null() saying "The do nothing
command for comments." before that (2BSD, file copyright 1979).
--steffen
next prev parent reply other threads:[~2017-04-19 22:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-18 20:48 Warren Toomey
2017-04-18 20:51 ` Ron Natalie
2017-04-18 21:45 ` Grant Taylor
2017-04-18 22:16 ` Ron Natalie
2017-04-18 22:40 ` Toby Thain
2017-04-19 18:36 ` Stephen Kitt
2017-04-19 20:35 ` Arthur Krewat
2017-04-19 0:50 ` Lyndon Nerenberg
2017-04-19 8:35 ` Andreas Kusalananda Kähäri
2017-04-19 16:31 ` Grant Taylor
2017-04-19 16:59 ` Andreas Kusalananda Kähäri
2017-04-19 17:36 ` Bakul Shah
2017-04-19 17:59 ` Grant Taylor
2017-04-20 20:13 ` Clem Cole
2017-04-20 20:17 ` Chet Ramey
2017-04-21 3:28 ` arnold
2017-04-21 3:43 ` Bakul Shah
2017-04-21 6:07 ` Steve Nickolas
2017-04-21 11:18 ` Clem cole
2017-04-21 13:20 ` Michael Kjörling
2017-04-18 20:56 ` Chet Ramey
2017-04-19 21:02 ` Sven Mascheck
2017-04-19 22:07 ` Steffen Nurpmeso [this message]
2017-04-20 0:31 ` shawn wilson
2017-04-20 0:35 ` shawn wilson
2017-04-20 3:50 ` Andy Kosela
2017-04-20 4:47 ` Warner Losh
2017-04-21 1:42 ` Nemo
2017-04-21 10:54 ` Ron Natalie
2017-04-21 14:22 ` Andy Kosela
2017-04-21 14:45 ` Ron Natalie
2017-04-22 2:46 ` Dave Horsfall
2017-04-20 16:39 ` Sven Mascheck
2017-04-20 21:42 ` Steffen Nurpmeso
2017-04-19 19:18 Doug McIlroy
2017-04-21 17:03 Doug McIlroy
2017-04-21 18:15 ` Clem Cole
2017-04-21 19:13 ` Steve Johnson
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