text: #!/usr/bin/python
  
  import sys
  import time
  import subprocess
  import json
  
  def usage(f, st):
  	f.write("Usage:\n")
  	f.write("    time_it.py file utility [argument ...]\n\n")
  	f.write("Writes running time of utility into file.\n")
  	return st
  
  def main(argv):
  	if 3 > len(argv):
  		return usage(sys.stderr, -1)
  	t = time.time()
  	ret = subprocess.call(argv[2:])
  	t = time.time() - t
  	if 0 == ret:
  		with open(argv[1], "w") as f:
  			json.dump({"dt":t}, f)
  	return ret
  
  if __name__ == "__main__":
  	sys.exit(main(sys.argv))
  