title: How can I install packages using pip according to the requirements.txt file from a local directory?
body: <p>Here is the problem:</p>
  <p>I have a <em>requirements.txt</em> file that looks like:</p>
  <pre class="lang-none prettyprint-override"><code>BeautifulSoup==3.2.0
  Django==1.3
  Fabric==1.2.0
  Jinja2==2.5.5
  PyYAML==3.09
  Pygments==1.4
  SQLAlchemy==0.7.1
  South==0.7.3
  amqplib==0.6.1
  anyjson==0.3
  ...
  </code></pre>
  <p>I have a local archive directory containing all the packages + others.</p>
  <p>I have created a new <a href="http://pypi.python.org/pypi/virtualenv" rel="noreferrer">virtualenv</a> with</p>
  <pre class="lang-none prettyprint-override"><code>bin/virtualenv testing
  </code></pre>
  <p>Upon activating it, I tried to install the packages according to <em>requirements.txt</em> from the local archive directory.</p>
  <pre class="lang-none prettyprint-override"><code>source bin/activate
  pip install -r /path/to/requirements.txt -f file:///path/to/archive/
  </code></pre>
  <p>I got some output that seems to indicate that the installation is fine:</p>
  <pre class="lang-none prettyprint-override"><code>Downloading/unpacking Fabric==1.2.0 (from -r ../testing/requirements.txt (line 3))
    Running setup.py egg_info for package Fabric
      warning: no previously-included files matching '*' found under directory 'docs/_build'
      warning: no files found matching 'fabfile.py'
  Downloading/unpacking South==0.7.3 (from -r ../testing/requirements.txt (line 8))
    Running setup.py egg_info for package South
  ....
  </code></pre>
  <p>But a later check revealed that none of the packages are installed properly. I cannot import the packages, and none are found in the site-packages directory of my virtualenv. So what went wrong?</p>