title: What am I doing wrong ? sed: -e expression #1, char 74: missing command
body: <p>I am running Ubuntu 14 and am attempting to use sed to find a specific line in a file.</p>
  
  <p>When I run the command</p>
  
  <pre><code>sed '/password\s[success=\d\sdefault=ignore]\spam_unix.so\sobscure\s+sha512/' testfile.txt
  </code></pre>
  
  <p>I get <code>sed: -e expression #1, char 74: missing command</code></p>
  
  <p>I am looking for the line:</p>
  
  <pre><code>password    [success=1 default=ignore]  pam_unix.so obscure sha512
  </code></pre>
  
  <p>What am I missing or doing wrong?</p>