err = err1
		}
		return err
	})
	return pr, nil
}

func (c *Cmd) childStdout() (*os.File, error) {
	return c.writerDescriptor(c.Stdout)
}

func (c *Cmd) childStderr(childStdout *os.File) (*os.File, error) {
	if c.Stderr != nil && interfaceEqual(c.Stderr, c.Stdout) {
		return childStdout, nil
	}
	return c.writerDescriptor(c.Stderr)
}