Weird behavior with redirecting stdin

Weird behavior with redirecting stdin

[Aryn Starr]

With these functions:

```
fcm () {
# Function for selecting a command interactively
        echo ${(F)commands} | fzf
}

teec () {
# Dumbed down version of a function that both echoes and copies to clipboard. (Current toy version just echoes.)
        local out="$(</dev/stdin)"
        print -r -- "$out"
}
```

I can do `fcm | teec` and it works correctly.
However, if I change `teec` to this:

```
teec () {
        echo 'echo hi' | { eval "$(</dev/stdin)" }
        local out="$(</dev/stdin)"
        print -r -- "$out"
}
```

Then running `fcm | teec` hangs (after printing `hi`) and doesn’t even get interrupted with ^D or ^C.
I don’t understand why these problems occur at all, and I have no idea how to go about fixing them ...

Re: Weird behavior with redirecting stdin

[Pier Paolo Grassi]

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hello, anyone has suggestions on this?
regards

Il giorno lun 2 set 2019 alle ore 15:59 Aryn Starr <
whereislelouch@icloud.com> ha scritto:

> With these functions:
>
> ```
> fcm () {
> # Function for selecting a command interactively
>         echo ${(F)commands} | fzf
> }
>
> teec () {
> # Dumbed down version of a function that both echoes and copies to
> clipboard. (Current toy version just echoes.)
>         local out="$(</dev/stdin)"
>         print -r -- "$out"
> }
> ```
>
> I can do `fcm | teec` and it works correctly.
> However, if I change `teec` to this:
>
> ```
> teec () {
>         echo 'echo hi' | { eval "$(</dev/stdin)" }
>         local out="$(</dev/stdin)"
>         print -r -- "$out"
> }
> ```
>
> Then running `fcm | teec` hangs (after printing `hi`) and doesn’t even get
> interrupted with ^D or ^C.
> I don’t understand why these problems occur at all, and I have no idea how
> to go about fixing them ...

Re: Weird behavior with redirecting stdin

[Roman Perepelitsa]

On Mon, Sep 2, 2019 at 3:59 PM Aryn Starr <whereislelouch@icloud.com> wrote:
> Then running `fcm | teec` hangs (after printing `hi`) and doesn’t even get interrupted with ^D or ^C.
> I don’t understand why these problems occur at all, and I have no idea how to go about fixing them ...

I don't know what's going on but here's a simplified test case that hangs:

    echo | fzf | { /bin/true; : "$(cat)" }

This also hangs:

    fzf | { /bin/true; : "$(cat)" }

I think this might be caused by fzf getting suspended when it tries to
write to the terminal. I'm just speculating though.

Roman.