title: How to copy a file with a timestam
body: <p>I would like to save in a variable the current time (I can do this)
  I then want to copy file a to file b and include the timestamp in file b.
  like this copy file1 file1.08-02-2019 (like a backup of the file)
  I can copy the file fine except when I add the timestamp?</p>
  
  <p>I can do the copy with no issues. I just can't get the copy to work with the timestamp variable in the dest file name</p>
  
  <pre><code>import shutil
  import datetime
  import os
  
  now = datetime.datetime.now()
  timestamp = str(now.strftime("%Y%m%d_%H:%M:%S"))
  
  os.system('copy C:\\Users\\kwhol\\my_python_code\\twp_pid_ctrl, C:\\Users\\kwhol\\my_python_code\\twp_pid_ctrl_backup'+'timestamp')
  </code></pre>
  
  <p>it takes the time stamp as literal meaning the word timestamp is in the dest file name not the actual value of the timestamp variable</p>