title: replace parameter values from a file using python regex
body: <p>I have file <code>load_file</code> which has contents like below (below is a trimmed version):
  i want to replace the values for certain params dynamically.
  for example, i want "BENCHMARK=EDA". the word 'BENCHMARK' may repeat mulitple times in the file.</p>
  
  <pre><code># Official BENCHMARK values are
  #       -SWBUILD
  #       -VDA
  #       -VDI
  #       -DATABASE
  #       -EDA
  #
  ##############################################################################
  BENCHMARK=VDI
  LOAD=10
  INCR_LOAD=10
  NUM_RUNS=10
  </code></pre>
  
  <p>i tried to do the following:</p>
  
  <pre><code>  import re
    with open(load_file, 'r') as file:
       filedata = file.read()
    filedata=re.sub('BENCHMARK=*','BENCHMARK=EDA',filedata)
  </code></pre>
  
  <p>the above regex function is not working as i expected.
  what am i missing in the regex method?</p>