text: # -*- coding: utf-8 -*-
  #!/usr/bin/env python
  ## last modified by Robert Liu at 7/29/2019
  ## This script is used to extract Date and Time from 'date' keyword of the input FITS header and write it to a new 'DTUTC' keyword, which is required by DMstack v17.0.1 (astrom_metadata_translator) but lacked in DECam pipeline after 2017/11.
  
  import re
  import sys
  import numpy as np
  from astropy.io import fits
  from astropy.io.fits import getdata
  
  if len(sys.argv) != 2:
      print("Usage: python fitsAddDT.py {fits_image}", file=sys.stderr)
      exit(1);
  fits1 = sys.argv[1]
  
  # Open the fits image with update mode. Read the string of DATE keyword.
  hdu = fits.open(fits1, mode='update')
  date_string = hdu[0].header['date']
  print('Date and time when this FITS was generated: ', date_string)
  
  # Append the date string to the end of header and save it as DTUTC.
  hdu[0].header.append(('DTUTC', date_string, 'Date Time'), end=True)
  hdu.close()
  
  print('DTUTC keyword added to the FITS file!\n')
  