import popen2

class grace:
    def __init__ (self):
        self.p = popen2.Popen3 ("xmgrace -noask -dpipe 0")

    def Command (self, cmd):
        if (cmd[-1] != '\n'):
            cmd = cmd + '\n'
        self.p.tochild.write (cmd)

    def Flush (self):
        self.p.tochild.flush()

    def Wait (self):
        return self.p.wait()
        
if (__name__ == "__main__"):
    g = grace()

    g.Command ("g0.s0 point 0,0")
    g.Command ("g0.s0 point 1,1")
    g.Flush()
    print "returned:", g.Wait()