Re: [PATCH v3 (resend)] tee: Add -q, --quiet, --silent option to not write to stdout

[Rodney W. Grimes]

> Hi Berny,
> 
> On 1/25/21 12:33 PM, Alejandro Colomar (man-pages) wrote:
> > On 1/25/21 5:03 AM, Bernhard Voelker wrote:
> >> On 1/24/21 9:01 PM, Alex Henrie wrote:
> >>> I am definitely interested. Bernhard Voelker seemed to express
> >>> interest as well, conditional on -q being added to POSIX first.[1]
> >>
> >> Just to clarify: I'm not as enthusiastic to add that option as it
> >> may have sounded.
> >>
> >> Let me put it like this: if -q once gets standardized by POSIX,
> >> then we'd take it over in the GNU tee implementation.
> >>
> >> Let me summarize so far:
> >> The suggestion is to solve the problem to save some data coming from
> >> a pipe as a different user.
> >> There are at least those known solutions:
> >> ?? - use > or >> redirection.
> >> ?? - use dd(1)
> >>
> >> I have the impression that a home for this feature was searched
> >> in any tool, and as tee(1) already knew how to write to a file,
> >> had the "append" feature, and is often used in pipes, it was
> >> tempting to add it there.
> >>
> >> But looking deeper, --quiet doesn't seem to fit well into 'tee'.
> >> It even contradicts to the title line in the man page:
> >> ?? "read from standard input and write to standard output and files"
> >>
> >> An off-tech argument: ask a local plumber if he'd would ever use
> >> a tee piece instead of a pipe end piece.? I guess he would only
> >> if he wouldn't have anything else at hand.
> > 
> > I never knew what 'tee' meant.? That makes sense now.
> > 
> >>
> >> A word to the proposed patch: what should happen, if the user does
> >> not give a file?
> >> ?? A | B | tee -q
> >> The patch just silently ignored that situation which feels wrong.
> >>
> >> Therefore, adding a feature which does not really fit is wrong, and
> >> contradicts the one-tool-for-one-purpose UNIX philosophy.
> >>
> > 
> > Agreed.
> > 
> >> OTOH I understand that there's a little gap in the tool landscape.
> >> Astonishingly, there doesn't seem to exist a trivial tool to redirect
> >> from standard input (or any other input file descriptor) to a file.
> >> I wrote such a little tool in the attached:
> >>
> >> ?? $ src/sink --help
> >> ?? Usage: src/sink [OPTION]... FILE
> >> ?? Copy input stream to FILE.
> >>
> >> ?? Mandatory arguments to long options are mandatory for short options 
> >> too.
> >>
> >> ???? -a, --append????????????? append to the given FILE, do not overwrite
> >> ???? -c, --create????????????? ensure to create FILE, error if exists
> >> ???? -i, --input-stream=FD???? read from stream FD instead of standard 
> >> input
> 
> 
> On second thought, this program does two things: read any FD, and write 
> to file.  I think it should be limited to writing to a file from stdin.
> 
> If you think there's a need for reading FDs other than 0, you might as 
> well want to pipe that information you're reading from them to filter it 
> with another tool, and this program doesn't allow you to do that, as 
> it's a sink.
> 
> So, I would remove '-i, --input-stream'.  (And if you think it's 
> missing, maybe write a program to read from any FD and write to stdout.)

Its name is cat(1)
cat /dev/fd/# >outputfile

> 
> Alex
> 
> 
> >>
> >> ?? The default input stream number FD is 0, representing the standard 
> >> input.
> >>
> >> This allows not only to copy data from standard input, but from any
> >> file descriptor open for reading.? It also allows control over
> >> how the output file will be opened (e.g. with O_CREAT|E_EXCL).
> >>
> >> The OPs case would look like:
> >>
> >> ?? echo 'foo' | sudo sink /etc/foo
> >> or
> >> ?? echo 'foo' | sudo sink -a /etc/foo? # append.
> >> or
> >> ?? echo 'foo' | sudo sink -c /etc/foo? # ensure creation of the file.
> >>
> >> I'm not sure if this will ever be considered for inclusion -
> >> I just did it "for fun". ;-)
> > 
> > Tested-by: Alejandro Colomar <alx.manpages@gmail.com>
> > Reviewed-by: Alejandro Colomar <alx.manpages@gmail.com>
> > 
> > Much better than my patch.? :-)
> > 
> >>
> >> Have a nice day,
> >> Berny
> >>
> > 
> > Have a nice day!
> > Alex
> > 
> > 
> > -- 
> > Alejandro Colomar
> > Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
> > http://www.alejandro-colomar.es/
> 
> 
> -- 
> --
> Alejandro Colomar
> Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
> http://www.alejandro-colomar.es/
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> 

-- 
Rod Grimes                                                 rgrimes@freebsd.org