1、http://bugs.python.org/issue6143 下载列表中的第二个ClearWindow.py（2009-6-15版本），右键另存为即可。
也可以复制以下内容，新建一个ClearWindow.py
"""Clear Window Extension
Version: 0.2Author: Roger D. Serwyroger.serwy@gmail.comDate: 2009-06-14It provides "Clear Shell Window" under "Options"
with ability to undo.Add these lines to config-extensions.def[ClearWindow]
enable=1
enable_editor=0
enable_shell=1
[ClearWindow_cfgBindings]
clear-window=<Control-Key-l>"""class ClearWindow:menudefs = [('options', [None,('Clear Shell Window', '<<clear-window>>'),]),]def __init__(self, editwin):self.editwin = editwinself.text = self.editwin.textself.text.bind("<<clear-window>>", self.clear_window2)self.text.bind("<<undo>>", self.undo_event) # add="+" doesn't workdef undo_event(self, event):text = self.texttext.mark_set("iomark2", "iomark")text.mark_set("insert2", "insert")self.editwin.undo.undo_event(event)# fix iomark and inserttext.mark_set("iomark", "iomark2")text.mark_set("insert", "insert2")text.mark_unset("iomark2")text.mark_unset("insert2")def clear_window2(self, event): # Alternative method# work around the ModifiedUndoDelegatortext = self.texttext.undo_block_start()text.mark_set("iomark2", "iomark")text.mark_set("iomark", 1.0)text.delete(1.0, "iomark2 linestart")text.mark_set("iomark", "iomark2")text.mark_unset("iomark2")text.undo_block_stop()if self.text.compare('insert', '<', 'iomark'):self.text.mark_set('insert', 'end-1c')self.editwin.set_line_and_column()def clear_window(self, event):# remove undo delegatorundo = self.editwin.undoself.editwin.per.removefilter(undo)# clear the window, but preserve current commandself.text.delete(1.0, "iomark linestart")if self.text.compare('insert', '<', 'iomark'):self.text.mark_set('insert', 'end-1c')self.editwin.set_line_and_column()# restore undo delegatorself.editwin.per.insertfilter(undo)2、将文件放到Python安装路径下：Python34\Lib\idlelib（我的是D:\Python34\Lib\idlelib）
3、在相同的路径下，找到config-extensions.def文件
4、用记事本打开，在最后粘上以下代码：
[ClearWindow]enable=1enable_editor=0enable_shell=1[ClearWindow_cfgBindings]clear-window=<Control-Key-l>
5、保存、关闭文件
6、重新启动IDLE，在option下面就有了Clear shell window 选项。快捷键是Ctrl + L