sys.argv command line parameters List, the first element of the program itself is the path sys.exit (n) to exit the program, when the normal exit Exit (0) sys.version Version Get Python interpreter sys.maxint largest Int value sys .path return path search module, using initialization value of environment variable PYTHONPATH sys.platform returns the operating system platform name sys.stdout.write ( 'please:') # standard output lead-out example of the progress bar, note, on py3 not, may be used instead of print val = sys.stdin.readline () [: - 1] # standard input sys.getrecursionlimit () # Get the maximum recursion layers sys.setrecursionlimit (1200) # set the maximum recursion layers sys.getdefaultencoding ( ) # get the interpreter default encoding sys.getfilesystemencoding # get stored memory data to a file in the default encoding