我在cygwin下使用virtualenv 1.9.1。创建每个virtualenv时没有任何选项(显然，除了目录名)。没有花哨的定制。
所有的虚拟环境都是新鲜的，也就是说我没有创建任何包装脚本，也没有编辑任何虚拟环境脚本。我完全确定我没有做任何特殊的事情(即除了滥用virtualenv，而不是采取使其操作受挫的行动)，这导致PYTHONPATH在多个virtualenv中缺席。
virtualenv激活脚本为每个新的virtualenv不创建PYTHONPATH。pip在$VIRTUAL_ENV/lib/python2.7/site-packages/<packagedir>(例如lib/python2.7/site-packages/html5lib)下安装软件包。
pip的行为似乎是可取的。然而，运行python(在激活virtualenv之后)会导致pip安装的包无法加载(即
更新:添加PYTHONPATH到activate确实"解决"了这个问题。显然，我不想手动维护它，也不必更新activate_this.py。我还是想知道为什么virtualenvs现在不能直接开箱工作。
解决方案是什么?Virtualenv过去从未这样做过。现在怎么了?
更新2:下面是使用-vv:
运行virtualenv的输出$ virtualenv -vv newvirtualenv
Creating newvirtualenv/lib/python2.7
Symlinking Python bootstrap modules
Symlinking newvirtualenv/lib/python2.7/config
Symlinking newvirtualenv/lib/python2.7/lib-dynload
Symlinking newvirtualenv/lib/python2.7/os.py
Ignoring built-in bootstrap module: posix
Symlinking newvirtualenv/lib/python2.7/posixpath.py
Cannot import bootstrap module: nt
Symlinking newvirtualenv/lib/python2.7/ntpath.py
Symlinking newvirtualenv/lib/python2.7/genericpath.py
Symlinking newvirtualenv/lib/python2.7/fnmatch.py
Symlinking newvirtualenv/lib/python2.7/locale.py
Symlinking newvirtualenv/lib/python2.7/encodings
Symlinking newvirtualenv/lib/python2.7/codecs.py
Symlinking newvirtualenv/lib/python2.7/stat.py
Symlinking newvirtualenv/lib/python2.7/UserDict.py
File newvirtualenv/lib/python2.7/lib-dynload/readline.dll already exists
Symlinking newvirtualenv/lib/python2.7/copy_reg.py
Symlinking newvirtualenv/lib/python2.7/types.py
Symlinking newvirtualenv/lib/python2.7/re.py
Symlinking newvirtualenv/lib/python2.7/sre.py
Symlinking newvirtualenv/lib/python2.7/sre_parse.py
Symlinking newvirtualenv/lib/python2.7/sre_constants.py
Symlinking newvirtualenv/lib/python2.7/sre_compile.py
File newvirtualenv/lib/python2.7/lib-dynload/zlib.dll already exists
Symlinking newvirtualenv/lib/python2.7/warnings.py
Symlinking newvirtualenv/lib/python2.7/linecache.py
Symlinking newvirtualenv/lib/python2.7/_abcoll.py
Symlinking newvirtualenv/lib/python2.7/abc.py
Symlinking newvirtualenv/lib/python2.7/_weakrefset.py
Creating newvirtualenv/lib/python2.7/site-packages
Writing newvirtualenv/lib/python2.7/site.py
Writing newvirtualenv/lib/python2.7/orig-prefix.txt
Writing newvirtualenv/lib/python2.7/no-global-site-packages.txt
Creating parent directories for newvirtualenv/include
Symlinking newvirtualenv/include/python2.7
Creating newvirtualenv/bin
New python executable in newvirtualenv/bin/python2.7
Changed mode of newvirtualenv/bin/python2.7 to 0755
Also creating executable in newvirtualenv/bin/python
Changed mode of newvirtualenv/bin/python to 0755
Testing executable with newvirtualenv/bin/python2.7 -c "import sys;out=sys.stdout;getattr(out, "buffer", out).write(sys.prefix.encode("utf-8"))"
Got sys.prefix result: u'/cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv'
Creating newvirtualenv/lib/python2.7/distutils
Writing newvirtualenv/lib/python2.7/distutils/__init__.py
Writing newvirtualenv/lib/python2.7/distutils/distutils.cfg
Using existing setuptools egg: /usr/lib/python2.7/site-packages/virtualenv_support/setuptools-0.6c11-py2.7.egg
Installing setuptools...
Running command /cygdrive/c/Users/ma...ualenv/bin/python2.7 -c "#!python
"""Bootstra...sys.argv[1:])
" -v /usr/lib/python2.7/s...ols-0.6c11-py2.7.egg
Processing setuptools-0.6c11-py2.7.egg
Copying setuptools-0.6c11-py2.7.egg to /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/lib/python2.7/site-packages
Adding setuptools 0.6c11 to easy-install.pth file
Saving /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/lib/python2.7/site-packages/easy-install.pth
Installing easy_install script to /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin
changing mode of /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin/easy_install to 755
Installing easy_install-2.7 script to /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin
changing mode of /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin/easy_install-2.7 to 755
Installed /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/lib/python2.7/site-packages/setuptools-0.6c11-py2.7.egg
Processing dependencies for setuptools==0.6c11
Finished processing dependencies for setuptools==0.6c11
...Installing setuptools...done.
Installing existing pip-1.3.1.tar.gz distribution: /usr/lib/python2.7/site-packages/virtualenv_support/pip-1.3.1.tar.gz
Installing pip...
Running command /cygdrive/c/Users/ma...ualenv/bin/python2.7 -x /cygdrive/c/Users/ma...env/bin/easy_install /usr/lib/python2.7/s...ort/pip-1.3.1.tar.gz
Processing pip-1.3.1.tar.gz
Running pip-1.3.1/setup.py -q bdist_egg --dist-dir /tmp/easy_install-ZP_VIv/pip-1.3.1/egg-dist-tmp-H3XBh_
warning: no files found matching '*.html' under directory 'docs'
warning: no previously-included files matching '*.txt' found under directory 'docs/_build'
no previously-included directories found matching 'docs/_build/_sources'
Adding pip 1.3.1 to easy-install.pth file
Installing pip script to /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin
Installing pip-2.7 script to /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/bin
Installed /cygdrive/c/Users/marcin/Documents/codeprojects/newvirtualenv/lib/python2.7/site-packages/pip-1.3.1-py2.7.egg
Processing dependencies for pip==1.3.1
Finished processing dependencies for pip==1.3.1
...Installing pip...done.
Writing newvirtualenv/bin/activate
Writing newvirtualenv/bin/activate.fish
Writing newvirtualenv/bin/activate_this.py
Writing newvirtualenv/bin/activate.csh
我在Win7上运行cygwin的Python。我已经安装了easy_install。然后是pip，然后是virtualenv。然后运行virtualenv newve，然后运行source newve/bin/activate，然后pip安装了一个包(IPython)。一切正常。我可以从python REPL中导入，程序可以工作，并且路径设置正确。PYTHONPATH在任何地方都不会被设置。我很困惑。
尝试重新安装所有内容?
编辑:发现cygwin包python-setuptools中有easy_install
我唯一能想到的是PYTHONPATH已经设置好了。由于Cygwin继承了所有Windows的环境变量，如果已经设置了PYTHONPATH, virtualenv将使用它而不是正确的目录。检查是否已经设置了Windows下的PYTHONPATH。如果是，请删除该文件，然后重试virtualenv。还要检查.bashrc文件，看看那里是否设置了PYTHONPATH。为什么你不能在Windows上使用普通的Python ?您正在编写POSIX脚本吗?