from sys import argv

 script,filename = argv

 txt = open(filename)

 print "Here's your file %r:" % filename

 print txt.read()

 txt.close()

 #将一个文件copy到另外一份文件中

 from sys import argv

 from os.path import exists

 script, from_file, to_file = argv

 print "Copying from %s to %s" % (from_file,to_file)

 input = open(from_file)

 indata = input.read()

 print "The input file is %d bytes long" % len(indata) #len(indata) 求长度的函数

 print "Does the output file exist? %r" % exists(to_file) #如果为TRUE，则覆盖；如果为False，则新建一个

 print "Ready, hit RETURN to continue,ctrl-c to abort.",raw_input()

 output = open(to_file, 'w') #必须开启写权限

 output.write(indata)         #把input内容写进去

 print "Alright, all done"

 output.close()

 # to double check output

 output1 = open(to_file)

 print output1.read()

 output1.close()

 input.close()