Determines whether the specified shell args have a redirect specification for
        the output. Returns a tuple of (usable args, filename, append).

def _redirect_split(self, args):
        """Determines whether the specified shell args have a redirect specification for
        the output. Returns a tuple of (usable args, filename, append).
        """
        if ">>" in args:
            append = True
            usable, filename = args.split(">>")
        elif ">" in args:
            append = False
            usable, filename = args.split(">")
        else:
            append = filename = None
            usable = args

        if filename is not None:
            return (usable, filename.strip(), append)
        else:
            return (usable, filename, append)