引发导入错误("无法导入设置，因为环境变量 %s 未定义

Question

关于这个错误，Stack上有几个问题，但是没有答案帮助我，奇怪的是，这个错误突然被提出，而之前一切都很好。

我所做的是重新启动服务器，突然出现了以下内容:

为什么这个错误突然可以出现，而我没有改变任何东西，我怎么能解决它?

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.7/bin/django-admin.py", line 5, in <module>
    management.execute_from_command_line()
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/management/__init__.py", line 261, in fetch_command
    klass = load_command_class(app_name, subcommand)
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/management/__init__.py", line 69, in load_command_class
    module = import_module('%s.management.commands.%s' % (app_name, name))
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/management/commands/runserver.py", line 8, in <module>
    from django.core.servers.basehttp import AdminMediaHandler, run, WSGIServerException, get_internal_wsgi_application
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/core/servers/basehttp.py", line 26, in <module>
    from django.views import static
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/views/static.py", line 95, in <module>
    template_translatable = ugettext_noop(u"Index of %(directory)s")
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/utils/translation/__init__.py", line 75, in gettext_noop
    return _trans.gettext_noop(message)
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/utils/translation/__init__.py", line 48, in __getattr__
    if settings.USE_I18N:
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/utils/functional.py", line 184, in inner
    self._setup()
  File "/Library/Python/2.7/site-packages/Django-1.4.5-py2.7.egg/django/conf/__init__.py", line 40, in _setup
    raise ImportError("Settings cannot be imported, because environment variable %s is undefined." % ENVIRONMENT_VARIABLE)
ImportError: Settings cannot be imported, because environment variable DJANGO_SETTINGS_MODULE is undefined.

Answer 1

每当我打开一个新的shell时，我都会运行这个脚本:

export PYTHONPATH=$PYTHONPATH:/Users/cole/Projects/Sites/my_project.com/my_project
export DJANGO_SETTINGS_MODULE=my_project.settings

更新:我编辑的脚本有点草率。所需要的是:

export PYTHONPATH=$PYTHONPATH:/Path/To/Project/Root/Directory
export DJANGO_SETTINGS_MODULE=my_project.settings

Answer 2

进入到manage.py可用的项目文件夹并运行:

python management .py shell

运行出错的django语句。