Input prompt with command substitution

[kwkelly]

I'm trying to write a bash script using inquirer for input, but when using command substitution, inquirer does not show the prompt.

Test script test.js

var inquirer = require('inquirer');

inquirer.prompt([
 {
    type: 'input',
    name: 'comments',
    message: 'Any comments on your purchase experience?',
    default: 'Nope, all good!'
}
]).then(answers => {
    console.log(answers)
});

To see the problem, try assigning the output of the prompt to a variable.

In a bash shell (maybe others):
ans=$(node test.js)

And nothing shows up, event though simply
node test.js
works just fine.

However, the read bash builtin seems to work fine with command substitution. The following will show a prompt:
$(read -p "Enter input: " input)

[kwkelly]

Interestingly, the bash builtin read uses stderr to display the prompt text. Redirecting stderr to stdout causes it to be captured in the variable.

[kwkelly]

Looks like this is probably solved by #519

But is it possible to write to /dev/tty instead of stderr?

[SBoudrias]

I don't think you'll be able to write to /dev/tty directly. Node only supports stdout and stderr as far as I know.

[kwkelly]

/dev/tty is just a file, so it can be written to as you would a file:

var fs  = require('fs');
var tty = fs.createWriteStream('/dev/tty');

tty.write('testing\n');

However, this might not be a great idea since I have no idea what the equivalent would be on Windows.

[SBoudrias]

@kwkelly actually, you can pass any stream as output. So it should work fine with the result of fs.createWriteStream.