为了查看是否安装了python模块，我在终端上运行了以下命令：
match=$(pydoc modules | grep $aModule)
出了点问题，现在它总是输出：
$ pydoc modules
Please wait a moment while I gather a list of all available modules...
Importing example package
demopkg1.__path__ before:
['/usr/local/lib/python2.7/dist-packages/PyMOTW/pkgutil/demopkg1']
demopkg1.__path__ after:
['/usr/local/lib/python2.7/dist-packages/PyMOTW/pkgutil/demopkg1']
Error: 'rho' must be an environment not NULL: detected in C-level eval
*** stack smashing detected ***: /usr/bin/python2.7 terminated
======= Backtrace: =========
/lib/i386-linux-gnu/libc.so.6(__fortify_fail+0x45)[0xb73f3eb5]
/lib/i386-linux-gnu/libc.so.6(+0x104e6a)[0xb73f3e6a]
/usr/lib/libR.so(+0x1c4964)[0xb2e93964]
/usr/lib/libR.so(+0xe5ddb)[0xb2db4ddb]
[0xbc246b4]
/usr/bin/python2.7(PyEval_EvalFrameEx+0x7c4)[0x812c6e4]
这是什么意思？我该如何解决？