Date: Mon, 21 Sep 2020 13:27:01 +0200 From: Polytropon <freebsd@edvax.de> To: "Steve O'Hara-Smith" <steve@sohara.org> Cc: freebsd-questions@freebsd.org Subject: Re: Error message output Message-ID: <20200921132701.61bf9883.freebsd@edvax.de> In-Reply-To: <20200921090937.fc1fbed5bdcd9615d77ea8f4@sohara.org> References: <20200920191108.22864e5c.freebsd@edvax.de> <528b2c90-18c4-9e95-a150-67344154c66c@holgerdanske.com> <20200921090937.fc1fbed5bdcd9615d77ea8f4@sohara.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 21 Sep 2020 09:09:37 +0100, Steve O'Hara-Smith wrote: > On Sun, 20 Sep 2020 22:12:24 -0700 > David Christensen <dpchrist@holgerdanske.com> wrote: > > > I have been migrating my programming style towards a data flow paradigm, > > which includes "command-line filters". So, an "ideal" command-line > > program or script would: > > > > * Use stdin for the input data. > > > > * Use stdout for the output data. > > > > * Use configuration files, command-line options and arguments, received > > signals and direct tty reads for out-of-band/ non-data input. > > This is where the standard set of unix devices is lacking, I have > long thought that there should be a stdctl then stdin/stdout are data flow > and stdtctl/stderr are control flow. At least that is something known in "mainframe land": While the file SYSPRINT is intended for program messages, i. e., things the program has to say about what it does, a different file is used for program output, for example SYSUT2 (but it doesn't have to be that one). But not everything is that clear: SYSIN can be used to control the program, but PARM= can also serve this purpose, while STDIN can instead contain input data for the program to process. And don't get me started about DCL... ;-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20200921132701.61bf9883.freebsd>