Calling interactive command inside widget

Calling interactive command inside widget

[Evgeny Zajcev]

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I always had next widget in my zprofile

  my-run-help () {
      words=(${=BUFFER})
      if [[ $words[1] = sudo ]]
      then
          run-help $words[2]
      else
          run-help $words[1]
      fi
      zle reset-prompt
  }

  zle -N my-run-help
  bindkey "^[^[h" run-help

so when I type in prompt something like "sudo adduser xxx" and want
interactive help on adduser I just press M-h

It was always working, however on my fresh Ubuntu install, I've got:

  adduser is /usr/sbin/adduser
  Missing filename ("less --help" for help)


I'v created simple widget like:

  just-run-man () {
      man man
  }
  zle -N just-run-man
  bindkey "^[^[h" just-run-man

And also got

  Missing filename ("less --help" for help)

What should I do to get desired behaviour?

I'm using zsh 5.0.2 (x86_64-pc-linux-gnu) under Ubuntu, my PAGER is less

thanks

-- 
lg

Re: Calling interactive command inside widget

[Peter Stephenson]

On Wed, 13 Apr 2016 00:58:04 +0300
Evgeny Zajcev <lg.zevlg@gmail.com> wrote:
> I'v created simple widget like:
> 
>   just-run-man () {
>       man man
>   }
>   zle -N just-run-man
>   bindkey "^[^[h" just-run-man
> 
> And also got
> 
>   Missing filename ("less --help" for help)

There's nothing much to go wrong in this ultra-simple example.  I would
suspect it's a problem not visible here, e.g. something associated with
less like the LESSOPEN variable has gone haywire.  To investigate, try
setting PAGER=more and see if that works.

pws

Re: Calling interactive command inside widget

[Bart Schaefer]

On Apr 13,  9:41am, Peter Stephenson wrote:
}
} There's nothing much to go wrong in this ultra-simple example. I would
} suspect it's a problem not visible here, e.g. something associated
} with less like the LESSOPEN variable has gone haywire. To investigate,
} try setting PAGER=more and see if that works.

I can reproduce from zsh -f on my older Ubuntu -- here is xtrace output:

burner% ls +my-run-help:2> words=( ls ) 
+my-run-help:3> [[ ls == sudo ]]
+my-run-help:7> man ls
Missing filename ("less --help" for help)
+my-run-help:9> zle reset-prompt
burner% which man
/usr/bin/man

Exporting PAGER=more silences the error but does not display a man page.
I have no LESSOPEN variable.

I replaced "man" with a function wrapper that captures strace and then
ran "man" from the command line and again from the widget.  Both times
"man" runs "pager -s" (which is a symlink through /etc/alternatives to
"less").

However, in the widget case, open("/dev/tty") returns 0, implying that
the standard input is closed, whereas in the command-line case the same
open() returns 3.  [This is from inside the forked "less".]

Looking more closely, "man" itself is invoked with standard input closed
which causes all sorts of confusion with its handling of pipes to all
the sub-processes it forks off (gunzip, nroff, etc.).  You can trivially
reproduce the error with:

burner% man ls <&-
Missing filename ("less --help" for help)
burner% ( man ls | less ) <&-
col: Bad file descriptor

This seems like a bug in "man" that should be reported to somebody, at
least Ubuntu if not upstream to Debian.

Meanwhile to fix the widget, just re-open /dev/tty:

  my-run-help () {
      words=(${=BUFFER})
      if [[ $words[1] = sudo ]]
      then
          run-help $words[2]
      else
          run-help $words[1]
      fi < /dev/tty
      zle reset-prompt
  }

You may want to throw a "zle -I" in there, but perhaps reset-prompt makes
it unnecessary.

Re: Calling interactive command inside widget

[frederik]

This is a bit tangential to your bug, but I don't know if you know
about various run-help-CMD helper functions:

http://stackoverflow.com/questions/32293262/how-to-make-zsh-run-help-to-ignore-sudo-and-get-help-about-the-following-com

I just learned about these a month ago.

Cheers,

Frederick

On Wed, Apr 13, 2016 at 12:58:04AM +0300, Evgeny Zajcev wrote:
> I always had next widget in my zprofile
> 
>   my-run-help () {
>       words=(${=BUFFER})
>       if [[ $words[1] = sudo ]]
>       then
>           run-help $words[2]
>       else
>           run-help $words[1]
>       fi
>       zle reset-prompt
>   }
> 
>   zle -N my-run-help
>   bindkey "^[^[h" run-help
> 
> so when I type in prompt something like "sudo adduser xxx" and want
> interactive help on adduser I just press M-h
> 
> It was always working, however on my fresh Ubuntu install, I've got:
> 
>   adduser is /usr/sbin/adduser
>   Missing filename ("less --help" for help)
> 
> 
> I'v created simple widget like:
> 
>   just-run-man () {
>       man man
>   }
>   zle -N just-run-man
>   bindkey "^[^[h" just-run-man
> 
> And also got
> 
>   Missing filename ("less --help" for help)
> 
> What should I do to get desired behaviour?
> 
> I'm using zsh 5.0.2 (x86_64-pc-linux-gnu) under Ubuntu, my PAGER is less
> 
> thanks
> 
> -- 
> lg

Re: Calling interactive command inside widget

[Sebastian Gniazdowski]

It's about having terminal attached to 0. I wrote a wrapper that runs
given interactive command from within Zle:

https://github.com/psprint/zsh-navigation-tools/blob/master/znt-usetty-wrapper

It's to be used in following way:

znt-usetty-wrapper some-interactive-command "$@"

via some widget file-function, like here:

https://github.com/psprint/zsh-navigation-tools/blob/master/znt-kill-widget

This looks quite like an overkill when compared to Bart's simple
</dev/tty, but it does some checking and searches for terminal also
via 2. Also, it restores previous 0 state. Maybe you'll like it

Best regards,
Sebastian Gniazdowski