From: Sven Mascheck via TUHS <tuhs@minnie.tuhs.org>
To: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] sh: cmd | >file
Date: Sun, 5 Jan 2020 14:45:23 +0100 [thread overview]
Message-ID: <20200105134523.GA417916@lisa.in-ulm.de> (raw)
In-Reply-To: <854eca1c-e5e5-5d8b-f5af-30cd1735096e@case.edu>
On Sat, Jan 04, 2020 at 09:41:59PM -0500, Chet Ramey wrote:
> On 1/4/20 6:53 PM, Dave Horsfall wrote:
> > Which reminds me: which Shell introduced "#" as a true comment?
>
> Define "true comment." The v7 shell had `#' as the comment character, but
> it only worked when in non-interactive shells. I think it was the Sys III
> shell that made it work when the shell was interactive.
>
> This is, incidentally, why bash has the `interactive_comments' option,
> which I saw in another message. BSD, which most of the GNU developers were
> using at the (pre-POSIX) time, used the v7 shell and didn't have
> interactive comments. When a sufficiently-advanced POSIX draft required
> them, we added it.
concerning "interactive" I think instead of the V7 sh you rather have
the BSD sh in mind here.
V7 sh didn't know # at all. At ATT it came with SysIII (both modes).
And keep in mind, stty erase defaulted to # on V7, even until SySV (and 3BSD),
and this character wouldn't have been handy anyway. 4+BSD changed this.
4.1BSD implemented #, and 4.3 BSD changed it to "non-interactive only".
(And all this is not to be confused with the # hack to exec to csh on 3+BSD,
only if it's the first character in a script.)
BTW, an academic yet funny example of : side effects is this
: `echo output 1>&2`
Sven
next prev parent reply other threads:[~2020-01-05 13:54 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-04 2:58 Doug McIlroy
2020-01-04 10:07 ` markus schnalke
2020-01-04 11:47 ` Robert Clausecker
2020-01-04 22:31 ` Chet Ramey
2020-01-04 21:02 ` Dave Horsfall
2020-01-04 21:06 ` Jon Steinhart
2020-01-05 0:03 ` Eric Allman
2020-01-05 1:49 ` Adam Thornton
2020-01-05 2:44 ` Chet Ramey
2020-01-05 8:15 ` Brantley Coile
2020-01-05 15:16 ` Chet Ramey
2020-01-04 21:11 ` Dave Horsfall
2020-01-04 21:39 ` Warner Losh
2020-01-04 22:19 ` Terry Jones
2020-01-04 22:33 ` Chet Ramey
2020-01-04 23:53 ` Dave Horsfall
2020-01-05 0:04 ` Andreas Kusalananda Kähäri
2020-01-05 2:41 ` Chet Ramey
2020-01-05 13:45 ` Sven Mascheck via TUHS [this message]
2020-01-05 15:18 ` Chet Ramey
2020-01-05 21:21 ` Dave Horsfall
2020-01-06 13:53 ` Chet Ramey
2020-01-06 15:42 ` Brantley Coile
2020-01-06 15:46 ` arnold
2020-01-06 16:13 ` Clem Cole
2020-01-06 20:44 ` arnold
2020-01-06 20:51 ` Steve Nickolas
2020-01-06 21:32 ` Clem Cole
2020-01-06 21:39 ` Brad Spencer
2020-01-06 21:29 ` Dave Horsfall
2020-01-06 21:55 ` Chet Ramey
2020-01-06 22:22 ` Dave Horsfall
2020-01-06 22:52 ` Dan Cross
2020-01-07 0:50 ` Adam Thornton
2020-01-06 22:10 ` Bakul Shah
2020-01-04 22:44 ` markus schnalke
2020-01-04 23:01 ` Terry Jones
2020-01-04 22:22 ` Dave Horsfall
-- strict thread matches above, loose matches on Subject: below --
2020-01-07 5:03 Brian Walden
2020-01-07 4:49 Brian Walden
2020-01-06 19:47 Doug McIlroy
2020-01-06 16:11 Brian Walden
2020-01-06 16:33 ` Clem Cole
2020-01-06 3:24 Brian Walden
2020-01-06 15:42 ` Richard Salz
2020-01-06 15:45 ` Brantley Coile
2020-01-03 12:45 markus schnalke
2020-01-03 14:00 ` Steffen Nurpmeso
2020-01-03 17:03 ` Brian Zick
2020-01-03 17:18 ` markus schnalke
2020-01-04 0:53 ` Sven Mascheck via TUHS
2020-01-04 20:41 ` Steffen Nurpmeso
2020-01-03 19:38 ` markus schnalke
2020-01-03 19:44 ` Warner Losh
2020-01-03 22:49 ` Michael Parson
2020-01-03 23:32 ` Dave Horsfall
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