编写一个Python脚本，将一个文件的内容拷贝到另一个文件

# -- coding: utf-8 --
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)

# we could do these two on one line too, how?
# input = open(from_file)
# indata = input.read()
indata = open(from_file).read()

#print "Here is indata: %r" % indata
#print
#print indata

print "The input file is %d bytes long" % len(indata)

print "Does the output file exists? %r" % exists(to_file)
print "Ready, hit RETURN to continue, CTRL-C to abort."
raw_input("RETURN or CTRL-C > ")

# 如果to_file不存在的话，程序会自动在脚本当前目录创建文件，文件名为你给的第二个参数
output = open(to_file, 'w')
output.write(indata)

print "Alright, all done."

output.close()
print
print indata

使用import整个模块的方式改写代码：

import sys #导入sys模块，可以读写文件内容
import os  #导入os模块，可以使用exists方法查询文件是否存在

script, from_file, to_file = sys.argv

input = open(from_file)
indata = input.read()

print "Does the output file exists? %r" % os.path.exists(to_file)
raw_input("continue? 'RETURN' for continue, 'CTRL-C' for abort. >")

output = open(to_file, 'w')
output.write(indata)

print "Alright, done."

output.close()
input.close()