text: import os
  
  """Take a file as an input. Split it by linelength to new files. Names of the new files
  are of the form filename_x_ply. Those files must not exist before this script is run,
  since it appends to files with these name.
  """
  
  if __name__ == "__main__":
  
      file_to_read_name = input("File to read: ")
  
      for ply_level in range(1, 43):
          output_file_name = file_to_read_name + "_" + str(ply_level) + "_ply"
          os.system("grep -x '.\{" + str(ply_level) + "\}' " +
                    file_to_read_name + " >> " + output_file_name)
  