title: How do I iterate over a range of numbers defined by variables in Bash?
body: <p>How do I iterate over a range of numbers in Bash when the range is given by a variable?</p>
  
  <p>I know I can do this (called "sequence expression" in the Bash <a href="http://www.gnu.org/software/bash/manual/bashref.html#Brace-Expansion" rel="noreferrer">documentation</a>):</p>
  
  <pre><code> for i in {1..5}; do echo $i; done
  </code></pre>
  
  <p>Which gives:</p>
  
  <blockquote>
    <p>1 <br/>
    2 <br/>
    3 <br/>
    4 <br/>
    5</p>
  </blockquote>
  
  <p>Yet, how can I replace either of the range endpoints with a variable? This doesn't work:</p>
  
  <pre><code>END=5
  for i in {1..$END}; do echo $i; done
  </code></pre>
  
  <p>Which prints:</p>
  
  <blockquote>
    <p>{1..5}</p>
  </blockquote>