I’m using IO.popen to communicate with an external process. At some
point the external process will exit either with a true or false
condition. It uses shell return codes (0 for true, 1 for false) to
indicate that this is happened. Is there a way to get the vale of this
return code from an IO object? Or will it be better to use Kernel.` or
suchlike. The $? system var doesn’t seem to be updated using IO.