Testing for the presence of input from stdin.

[Will McDonald]

On 23/01/06, Diez B. Roggisch <deets at nospam.web.de> wrote:
> > I can get the script to behave as expected when content's piped to it
> > using sys.stdin but I'd like to know that there's data coming from
> > stdin or fail and print the useage again. Is there a simple way to
> > achieve this?
>
> There are more experienced UNIXers here, but from my POV I don't see how
> that can happen. The reason is simply that
>
>  - sys.stdin alwasy exists (unless you close it yourself)
>
>  - in a pipe (which this essentially is) there is now way to know if there
> is more date to come or not, except for the "broken pipe" error - but that
> won't happen to you, as sys.stdin is not broken just because there is
> currently no data arriving.

That's a good point. I did wonder if it'd just have to sit there
waiting for input much like cat would. I think that's preferable, and
simpler :), than implementing timeouts.

Thanks.

Will.