title: Adding a leading zero to a float number in a bash script
body: <p>My script</p>
  
  <pre><code>#!/bin/bash
  echo -n "number 1 :";
  read number1
  echo -n "number 2 :";
  read number2    
  jlh=$(echo $number1 + $number2 | bc -l | sed 's/^\./0./');
      echo "your result : $number1 + $number2 = $jlh "
  </code></pre>
  
  <p>if input for number 1 is <code>-1</code> , and number 2 is <code>0.9</code>, why the result only <code>-.1</code>.</p>
  
  <p>I want to show the zero like this.</p>
  
  <pre><code>Your result : -1 + 0.9 = -0.1
  </code></pre>
  
  <p>How I can do it?</p>