class windowClass(wx.Frame):

    def __init__(self, *args, **kwargs):
        super(windowClass, self).__init__(*args, **kwargs)
        self.linuxGUI()
        
        self.Move((500, 100))
        self.Centre()
        self.Show()

    def linuxGUI(self):
        panel = wx.Panel(self, wx.ID_ANY)
        wx.StaticText(panel, self.command)
        self.Show(True)

    def command(self):
        subprocess.Popen('free')
        
        

def Main():
    app = wx.App()
    windowClass(None)
    app.MainLoop()

Main()