title: I need to replace a string using SED with an url
body: <p>When I use a normal value like <code>a=10</code></p>
  
  <p>I am able to get the sed find/replace working</p>
  
  <pre><code>  sed -e "s/xxx/$a/g" a.txt
  </code></pre>
  
  <p>But when I try to use a variable like <code>a=http://xyz.com</code></p>
  
  <p><code>sed -e "s/xxx/$a/g" a.txt</code> is not working...</p>
  
  <p>Its throwing unknown option error which I assume is due to the escape characters that are present over the variable</p>