text: """
  COMMAND-LINE SPECIFIC STUFF
  =============================================================================
  
  The rest of the code is specifically for handling the case where Python
  Markdown is called from the command line.
  """
  
  import markdown
  import sys
  import logging
  from logging import DEBUG, INFO, WARN, ERROR, CRITICAL
  
  EXECUTABLE_NAME_FOR_USAGE = "python markdown.py"
  """ The name used in the usage statement displayed for python versions < 2.3.
  (With python 2.3 and higher the usage statement is generated by optparse
  and uses the actual name of the executable called.) """
  
  OPTPARSE_WARNING = """
  Python 2.3 or higher required for advanced command line options.
  For lower versions of Python use:
  
        %s INPUT_FILE > OUTPUT_FILE
  
  """ % EXECUTABLE_NAME_FOR_USAGE
  
  def parse_options():
      """
      Define and parse `optparse` options for command-line usage.
      """
  
      try:
          optparse = __import__("optparse")
      except:
          if len(sys.argv) == 2:
              return {'input': sys.argv[1],
                      'output': None,
                      'safe': False,
                      'extensions': [],
                      'encoding': None }, CRITICAL
          else:
              print(OPTPARSE_WARNING)
              return None, None
  
      parser = optparse.OptionParser(usage="%prog INPUTFILE [options]")
      parser.add_option("-f", "--file", dest="filename", default=sys.stdout,
                        help="write output to OUTPUT_FILE",
                        metavar="OUTPUT_FILE")
      parser.add_option("-e", "--encoding", dest="encoding",
                        help="encoding for input and output files",)
      parser.add_option("-q", "--quiet", default = CRITICAL,
                        action="store_const", const=CRITICAL+10, dest="verbose",
                        help="suppress all messages")
      parser.add_option("-v", "--verbose",
                        action="store_const", const=INFO, dest="verbose",
                        help="print info messages")
      parser.add_option("-s", "--safe", dest="safe", default=False,
                        metavar="SAFE_MODE",
                        help="safe mode ('replace', 'remove' or 'escape'  user's HTML tag)")
      parser.add_option("-o", "--output_format", dest="output_format", 
                        default='xhtml1', metavar="OUTPUT_FORMAT",
                        help="Format of output. One of 'xhtml1' (default) or 'html4'.")
      parser.add_option("--noisy",
                        action="store_const", const=DEBUG, dest="verbose",
                        help="print debug messages")
      parser.add_option("-x", "--extension", action="append", dest="extensions",
                        help = "load extension EXTENSION", metavar="EXTENSION")
  
      (options, args) = parser.parse_args()
  
      if not len(args) == 1:
          parser.print_help()
          return None, None
      else:
          input_file = args[0]
  
      if not options.extensions:
          options.extensions = []
  
      return {'input': input_file,
              'output': options.filename,
              'safe_mode': options.safe,
              'extensions': options.extensions,
              'encoding': options.encoding,
              'output_format': options.output_format}, options.verbose
  
  def run():
      """Run Markdown from the command line."""
  
      # Parse options and adjust logging level if necessary
      options, logging_level = parse_options()
      if not options: sys.exit(0)
      if logging_level: logging.getLogger('MARKDOWN').setLevel(logging_level)
  
      # Run
      markdown.markdownFromFile(**options)
  