title: redirecting output of pexpect to a file
body: <p>I tried to capture the output of pexpect in a file.</p>
  
  <pre><code>Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56)
  [GCC 4.4.3] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import pexpect
  &gt;&gt;&gt; child = pexpect.spawn('iostat 3')
  &gt;&gt;&gt; fout = file('mylogfile.txt','w')
  &gt;&gt;&gt; child.logfile = fout  
  </code></pre>
  
  
  
  <pre><code>tazim@webdev:~/webexample$ ps -ef | grep iostat
  tazim     4683  4675  0 12:49 pts/3    00:00:00 /usr/bin/iostat 3
  tazim     4685  4560  0 12:51 pts/2    00:00:00 grep --color=auto iostat
  </code></pre>
  
  <p>However <code>mylogfile.txt</code> does not receives the output. The file is created but is empty.</p>