title: In BASH convert a string with . in float
body: <p>I have a string that represent a float:</p>
  
  <pre><code>echo $NUM
  5.03
  </code></pre>
  
  <p>I need to multiply this number for MEGA. If I do it directly:</p>
  
  <pre><code>MEGA="1000"
  result=$(($NUM*$MEGA))
  </code></pre>
  
  <p>I receive an error:</p>
  
  <pre><code>syntax error: invalid arithmetic operator (error token is ".03 * 1000")
  </code></pre>