How to obtain a simple use-case: redirect filtered data into file, unfiltered to the terminal?

How to obtain a simple use-case: redirect filtered data into file, unfiltered to the terminal?

[Sebastian Gniazdowski]

Hello,
I have a simple use-case that I would want to implement:
1. There is an application that outputs colorized logs.
2. I want the logs to go into a file (say `operation.log') filtered,
i.e. without colors.
3. But at the same time still go to the terminal unfiltered.
4. I want the application to have a positive response from the
iatty(1) function, i.e. that the application is thinking that the
output is to the terminal (well, it really *is*, it's just that it.
*also* goes to the file).

So writing one sentence: a terminal application outputting logs
filtered-and-redirected into a file, preserving the connection and
output to the terminal, i.e. isatty(1) answers positively for the app.

I tried with multios:

scrapy crawl 2nd_MyDom "$@" "${optarray[@]}" \
    > >(ansifilter >>! "scrapy.slog") 1> >/dev/tty

But this solution doesn't realize the 4th item – it doesn't provide
isatty(1) positive response for the app.

-- 
Sebastian Gniazdowski
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Blog: http://zdharma.org

Re: How to obtain a simple use-case: redirect filtered data into file, unfiltered to the terminal?

[Eric Cook]

On 2/7/19 8:12 AM, Sebastian Gniazdowski wrote:
> Hello,
> I have a simple use-case that I would want to implement:
> 1. There is an application that outputs colorized logs.
> 2. I want the logs to go into a file (say `operation.log') filtered,
> i.e. without colors.
> 3. But at the same time still go to the terminal unfiltered.
> 4. I want the application to have a positive response from the
> iatty(1) function, i.e. that the application is thinking that the
> output is to the terminal (well, it really *is*, it's just that it.
> *also* goes to the file).

Implement logging in the application.

Re: How to obtain a simple use-case: redirect filtered data into file, unfiltered to the terminal?

[Bart Schaefer]

On Thu, Feb 7, 2019 at 5:12 AM Sebastian Gniazdowski
<sgniazdowski@gmail.com> wrote:
>
> So writing one sentence: a terminal application outputting logs
> filtered-and-redirected into a file, preserving the connection and
> output to the terminal

The minimal syntax of the "script" command is "script outputfile
command" ... so let's use zsh tools to create the outputfile, and
leave managing the tty stuff to "script":

script >(ansifilter >>! scrapy.slog) scrapy crawl 2nd_MyDom "$@"
"${optarray[@]}"

This will say something like
  Script started, output file is /dev/fd/12
which you can get rid of by "script -q ...".