Python - 非常奇怪的sys.path行为

Question

sys.path [0]的条目是'/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode'。 Python文档说这应该是脚本的工作目录。任何想法可能会发生什么？

当我从交互式解释器运行Python并执行import sys; print sys.path[0];时，它打印''这似乎是正确的。

但是，当我的Python脚本从Perl脚本中调用时，我得到了sys.path[0]的上述条目。

其他信息：

• 我跑的Python 2.7。
• 我在Ubuntu 11.10 64位。
• 我的工作目录应该是到/ mnt/galaxyData /自定义/ MSG_toy
• perl脚本和Python脚本它调用位于在/ mnt/galaxyData /自定义/ MSG_toy /味精（味精目录是，如果一个符号链接它很重要）

这里是一切的sys.path中：

['/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode', 
'/mnt/galaxyData/custom/msg', 
'/usr/local/lib/python2.7/dist-packages/bx_python-0.7.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pip-1.0.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/amqplib-1.0.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/BeautifulSoup-3.2.0-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/boto-2.1.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Fabric-1.3.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/ssh-1.7.9-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/ipython-0.11-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Logbook-0.3-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/lxml-2.3.2-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/Mako-0.5.0-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/MarkupSafe-0.15-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/nose-1.1.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/numpy-1.6.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/Paste-1.7.5.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/PasteScript-1.7.5-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/PasteDeploy-1.5.0-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/python_cjson-1.0.5-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pyOpenSSL-0.13-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/PyYAML-3.10-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/Routes-1.12.3-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/simplejson-2.2.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/Sphinx-1.1.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/docutils-0.8.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Jinja2-2.6-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Pygments-1.4-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/WebHelpers-1.3-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/WebOb-1.2b2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/xlrd-0.7.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Cython-0.15.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/Pyrex-0.9.9-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/virtualenv-1.6.4-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/tornado-2.1.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/Twisted-11.0.0-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/biopython-1.58-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/celery-2.4.2-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/pysam-0.5-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/python_dateutil-1.5-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/kombu-1.4.3-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/anyjson-0.3.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/DendroPy-3.9.0-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/HTSeq-0.5.3p3-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/networkx-1.5-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/pandas-0.5.0-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pygr-0.8.2-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pysparse-1.2_dev-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/rpy2-2.2.4dev_20111114-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/rpy2_bioconductor_extensions-0.2.5_dev-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/scikits.learn-0.8.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/scikits.statsmodels-0.3.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/scipy-0.10.0-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/sympy-0.7.1-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/CouchDB-0.8-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/h5py-2.0.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/MySQL_python-1.2.3-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pymongo-2.0.1-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pysqlite-2.6.3-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/psycopg2-2.4.2-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/SQLAlchemy-0.7.3-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/gnuplot_py-1.8-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/PIL-1.1.7-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/pydot-1.0.25-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/pyparsing-1.5.6-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/pygooglechart-0.3.0-py2.7.egg', 
'/usr/local/lib/python2.7/dist-packages/reportlab-2.5-py2.7-linux-x86_64.egg', 
'/usr/local/lib/python2.7/dist-packages/bcbio_nextgen-0.3a-py2.7.egg', 
'/mnt/galaxyData/custom/bin/python_libs', 
'/mnt/galaxyData/custom/MSG_toy', 
'/usr/lib/python2.7', 
'/usr/lib/python2.7/plat-linux2', 
'/usr/lib/python2.7/lib-tk', 
'/usr/lib/python2.7/lib-old', 
'/usr/lib/python2.7/lib-dynload', 
'/usr/local/lib/python2.7/dist-packages', 
'/usr/lib/python2.7/dist-packages', 
'/usr/lib/python2.7/dist-packages/PIL', 
'/usr/lib/python2.7/dist-packages/gst-0.10', 
'/usr/lib/python2.7/dist-packages/gtk-2.0', 
'/usr/lib/pymodules/python2.7', 
'/usr/lib/python2.7/dist-packages/ubuntu-sso-client', 
'/usr/lib/python2.7/dist-packages/wx-2.8-gtk2-unicode'] 

Answer 1

这应做到：

import os; print(os.path.dirname(__file__)) 

向@AndiDog致敬。

编辑：还介意的__file__可用性和价值的文档（here和here）在提示：

预定义的可写属性：__name__是模块的名称; __doc__是模块的文档字符串，如果不可用则为None; __file__是从模块加载的文件的路径名，如果它是从文件加载的。对于静态链接到解释器的C模块，__file__属性不存在;对于从共享库动态加载的扩展模块，它是共享库文件的路径名。

__file__被设置为模块加载器提供的名称。如果加载程序没有提供文件名信息，则将此变量设置为无。