1 sys.argv 命令行参数List，第一个元素是程序本身路径 2 sys.exit(n) 退出程序，正常退出时exit(0) 3 sys.version 获取Python解释程序的版本信息 4 sys.maxint 最大的Int值 5 sys.path 返回模块的搜索路径，初始化时使用PYTHONPATH环境变量的值 6 sys.platform 返回操作系统平台名称 7 sys.stdout.write('please:') 8 val = sys.stdin.readline()[:-1]
help信息：
DESCRIPTION This module provides access to some objects used or maintained by the interpreter and to functions that interact strongly with the interpreter. Dynamic objects: argv -- command line arguments; argv[0] is the script pathname if known path -- module search path; path[0] is the script directory, else '' modules -- dictionary of loaded modules displayhook -- called to show results in an interactive session excepthook -- called to handle any uncaught exception other than SystemExit To customize printing in an interactive session or to install a custom top-level exception handler, assign other functions to replace these. stdin -- standard input file object; used by input() stdout -- standard output file object; used by print() stderr -- standard error object; used for error messages By assigning other file objects (or objects that behave like files) to these, it is possible to redirect all of the interpreter's I/O. last_type -- type of last uncaught exception last_value -- value of last uncaught exception last_traceback -- traceback of last uncaught exception These three are only available in an interactive session after a traceback has been printed.