title: subprocess.Popen() error (No such file or directory) when calling command with arguments as a string
body: <p>I am trying to count the number of lines in a file using Python functions. Within the current directory, while <code>os.system("ls")</code> finds the file, the command <code>subprocess.Popen(["wc -l filename"], stdout=subprocess.PIPE</code>) does not work.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>&gt;&gt;&gt; import os
  &gt;&gt;&gt; import subprocess
  &gt;&gt;&gt; os.system("ls")
  sorted_list.dat
  0
  &gt;&gt;&gt; p = subprocess.Popen(["wc -l sorted_list.dat"], stdout=subprocess.PIPE)File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  File "/Users/a200/anaconda/lib/python2.7/subprocess.py", line 710, in __init__
      errread, errwrite)
  File "/Users/a200/anaconda/lib/python2.7/subprocess.py", line 1335, in _execute_child
      raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>