passing stdin to a command called in a function

Question

I have a python script that I wrapped in a function call. The script is scr and the function is function scr {python (Join-Path $ENV:HOME "bin\scr") $args}. When I call python directly, it accepts stdin fine. So echo hello | python bin\scr works. But when I call the function (echo hello | scr), then stdin is not passed from the pipe to the python script but seems to still come from the terminal. How can I fix this?

You can extend your function with the `[CmdletBinding]` attribute. This will allow you to pipe to it. [See here](https://technet.microsoft.com/en-us/library/hh847872.aspx) for more info — arco444, Jul 16 '15 at 13:51

score 2 · Accepted Answer · answered Jul 16 '15 at 15:07

You can use $input automatic variable, which represent pipeline input to your function. Also you can use $MyInvocation.ExpectingInput to find out did your function expect any pipeline input or not.

function scr {
    $MyArgs=(Join-Path $ENV:HOME "bin\scr"),$args
    if($MyInvocation.ExpectingInput){
        $input | python @MyArgs
    }else{
        python @MyArgs
    }
}

passing stdin to a command called in a function

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