title: Resolve bash variable containted in another variable
body: <p>I have code like that:</p>
  
  <pre><code>TEXT_TO_FILTER='I would like to replace this $var to proper value
                  in multiline text'
  var=variable
  </code></pre>
  
  <p>All I want to get is:</p>
  
  <pre><code>TEXT_AFTER_FILTERED="I'd like to replace this variable to proper value"
  </code></pre>
  
  <p>So I did:</p>
  
  <pre><code>TEXT_AFTER_FILTERED=`eval echo $TEXT_TO_FILTER`
  TEXT_AFTER_FILTERED=`eval echo $(eval echo $TEXT_TO_FILTER)`
  </code></pre>
  
  <p>Or even more weirder things, but without any effects. 
  I remember that someday I had similar problem and I did something like that:</p>
  
  <pre><code>cat &lt;&lt; EOF &gt; tmp.sh
  echo $TEXT_TO_FILTER
  EOF
  chmod +x tmp.sh
  TEXT_AFTER_FILTERED=`. tmp.sh`
  </code></pre>
  
  <p>But this solution seems to be to much complex.
  Have any of You heard about easier solution?</p>