title: Ansible Command module says that '|' is illegal character
body: <p>I am using Ansible to deploy my project and I trying to check if an specified package is installed, but I have a problem with it task, here is the task:</p>
  
  <pre><code>- name: Check if python-apt is installed
    command: dpkg -l | grep python-apt
    register: python_apt_installed
    ignore_errors: True
  </code></pre>
  
  <p>And here is the problem:</p>
  
  <pre><code>$ ansible-playbook -i hosts idempotent.yml
  
  PLAY [lxc-host] *************************************************************** 
  
  GATHERING FACTS *************************************************************** 
  ok: [10.0.3.240]
  
  TASK: [idempotent | Check if python-apt is installed] ************************* 
  failed: [10.0.3.240] =&gt; {"changed": true, "cmd": ["dpkg", "-l", "|", "grep", "python-apt"], "delta": "0:00:00.015524", "end": "2014-07-10 14:41:35.207971", "rc": 2, "start": "2014-07-10 14:41:35.192447"}
  stderr: dpkg-query: error: package name in specifier '|' is illegal: must start with an alphanumeric character
  ...ignoring
  
  PLAY RECAP ******************************************************************** 
  10.0.3.240                 : ok=2    changed=1    unreachable=0    failed=0 
  </code></pre>
  
  <p>Why is illegal this character <strong>'|'</strong> . </p>