`sdtin / stdout` default values for File? about argparse

[akamensky]

That is a great question. Which also (going one step further) would be "And how about pipes?".

As nice as it would be to have library that does everything (i.e. like systemd tries to do absolutely everything), I think in this specific case it would be better to keep this library do what it is intended to do, namely -- parsing command line arguments.

You always can achieve the same what you want in your own code. Such as:

s := p.String("s", "string", &argparse.Options{...})
p.Parse(os.Args)
switch *s {
case "stdin":
    // read value from stdin
default:
    // use value as provided on CLI
}

Also on Unix systems at least the de-facto old standing standard is to use - for stdin, though in your app you can do this at your own discretion.