8 Apr
8 Apr
3:32 a.m.
New subject: Why does shell write to stderr?
Douglas McIlroy wrote in
<CAKH6PiXBEZPyjUk=DD8moA8ZnA2kpfk=Z7+6WwckSQb5HPUX3Q(a)mail.gmail.com>:
|How would you wish to interact with
| /bin/bash >file
While the POSIX standard defines an interactive shell as one with
STDIN and STDERR being a terminal, i think the NetBSD shell did
not until not too long (< half a decade?) ago, and the mailer you
were using for a long time does not to this day. (Unfortunately.)
APPLICATION USAGE
Standard input and standard error are the files that determine
whether a shell is interactive when -i is not specified. For
example:
sh > file
and:
sh 2> file
create interactive and non-interactive shells,
respectively. Although both accept terminal input, the results of
error conditions are different, as described in Section 2.8.1 (on
page 2363); in the second example a redirection error encountered
by a special built-in utility aborts the shell.
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
3:36 a.m.
New subject: Why does shell write to stderr?
On Thu, Apr 7, 2022 at 5:13 PM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
How would you wish to interact with
/bin/bash >file
I am not sure. I could see the argument either way right now.
On Thu, Apr 7, 2022 at 5:13 PM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
How would you wish to interact with
/bin/bash >file
> Doug
>
4:15 a.m.
New subject: Why does shell write to stderr?
I am indeed a throwback but programs calling stat or stty to examine their
I/O state before deciding how to behave was a shock when I first saw it
done, in Berkeley ls I think, and still feels misguided. I understand the
convenience but not every convenience is good engineering.
-rob
On Fri, Apr 8, 2022 at 7:38 AM Richard Salz <rich.salz(a)gmail.com> wrote:
On Thu, Apr 7, 2022 at 5:13 PM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
How would you wish to interact with
/bin/bash >file
I am not sure. I could see the argument either way right now.
On Thu, Apr 7, 2022 at 5:13 PM Douglas McIlroy <
douglas.mcilroy(a)dartmouth.edu> wrote:
How would you wish to interact with
/bin/bash >file
> Doug
>
4:30 a.m.
New subject: Why does shell write to stderr?
I also had extreme WTF the first time I looked in code and saw an
isatty() guard over some activity.
"this program processes stdin to stdout, except.. if I decide
otherwise" never appeared in man pages.
But that said, it sort of made sense. Why ring bell in an editor, if
you know the input pipe side can't hear it? A tty is a rather strange
device being the join over stdout, stdin and stderr, and there is a
(tiny?) set of things which need to know.
more for instance, probably needs to know that waiting for a command
to move pagination onward if there is no controlling terminal is not
sensible. If you want your input in chunks, more is not the way to do
it.
I hate special cases. This is why people say english is so hard to
learn but really all languages have them, its just that english having
stolen words from everywhere has more instances of isatty() than
others.
-G
5:51 a.m.
New subject: Why does shell write to stderr?
If you never ring the bell in the editor, the issue never comes up, the
code is simpler, and there's less to understand.
-rob
On Fri, Apr 8, 2022 at 8:33 AM George Michaelson <ggm(a)algebras.org> wrote:
I also had extreme WTF the first time I looked in code
and saw an
isatty() guard over some activity.
"this program processes stdin to stdout, except.. if I decide
otherwise" never appeared in man pages.
But that said, it sort of made sense. Why ring bell in an editor, if
you know the input pipe side can't hear it? A tty is a rather strange
device being the join over stdout, stdin and stderr, and there is a
(tiny?) set of things which need to know.
more for instance, probably needs to know that waiting for a command
to move pagination onward if there is no controlling terminal is not
sensible. If you want your input in chunks, more is not the way to do
it.
I hate special cases. This is why people say english is so hard to
learn but really all languages have them, its just that english having
stolen words from everywhere has more instances of isatty() than
others.
-G
9 Apr
9 Apr
7:46 a.m.
New subject: Why does shell write to stderr?
On Thu, Apr 7, 2022 at 7:53 PM Rob Pike <robpike(a)gmail.com> wrote:
If you never ring the bell in the editor, the issue never comes up, the
code is simpler, and there's less to understand.
Well, yes. And by the same token, you can eliminate the complexities of
i18n by having only one diagnostic, namely "?" (or by pretending all the
world is anglophone).
But setting aside for the moment this style of argumentation, let's
consider directory colorization. I have no dog in this fight, as I set all
my terminals to black-on-white as God and Gutenberg intended, and set TERM
to vt100 so the colors can't be changed. However, the feature seems to be
extremely popular, and can't be readily done outboard in a pipeline],
unlike most of the infamous options of cat(1). As things stand, the X3.64
control sequences output by colorization are *not* suppressed when the
output of ls isn't a terminal, which means I have had to write a stripper
for them. Another example is cal(1), which tries to output the current day
in reverse video, which is equally annoying but fortunately can be
suppressed more easily by piping it through more(1).
7:53 a.m.
New subject: Why does shell write to stderr?
Kinda think you're running Rob's argument for him by inductive reasoning.
If those other progroids read env() they could learn if colour was du Jure
or not. No isatty() required.
I think there always will be some special cases and like cardamom pods in
curry you hate them when you bite them.
G
10 Apr
10 Apr
12:05 a.m.
New subject: Why does shell write to stderr?
John Cowan wrote in
<CAD2gp_RsFWGUtj-9QDKSG3h8Otxb0ZY5M7G00ZAjV=dKEg+Rsw(a)mail.gmail.com>:
|On Thu, Apr 7, 2022 at 7:53 PM Rob Pike <robpike(a)gmail.com> wrote:
|If you never ring the bell in the editor, the issue never comes up, the
|> code is simpler, and there's less to understand.
|
|Well, yes. And by the same token, you can eliminate the complexities of
|i18n by having only one diagnostic, namely "?" (or by pretending all the
|world is anglophone).
|
|But setting aside for the moment this style of argumentation, let's
|consider directory colorization. I have no dog in this fight, as I set all
|my terminals to black-on-white as God and Gutenberg intended, and set TERM
Johannes Gutenberg? The bible was in parts red-on-white at least,
and had beautiful coloured paintings, too. (They did not know
about the communist Charlie Chaplin and his Modern Times by then.)
...
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
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days inactive
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8 comments
6 participants
participants (6)
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Douglas McIlroy -
George Michaelson -
John Cowan -
Richard Salz -
Rob Pike -
Steffen Nurpmeso