title: Bash: replace list of numbers in column with sequential list
body: <p>I need to replace the first column of numbers with a list of sequential numbers.  The file looks like:</p>
  
  <pre><code> 1     the   quick   brown     fox   jumps    over  
   7     the    lazy     dog     the   quick   brown
  13     fox   jumps    over     the    lazy     dog
  26     the   quick   brown     fox   jumps    over
  31     the    lazy     dog     the   quick   brown
  </code></pre>
  
  <p>and I need:</p>
  
  <pre><code> 1     the   quick   brown     fox   jumps    over  
   2     the    lazy     dog     the   quick   brown
   3     fox   jumps    over     the    lazy     dog
   4     the   quick   brown     fox   jumps    over
   5     the    lazy     dog     the   quick   brown
  </code></pre>
  
  <p>Any solutions with bash/sed/awk would be appreciated.</p>