from sys import argv

script,filename = argv

print "We‘re going to erase %r."% filename
print "If you don‘t want that,hit CTRL-C (^C)."
print "If you want that,hit RETURN."

raw_input("?")

print "Opening the file..."
target = open(filename,‘w‘)

print "Truncating the file.Goodbye..."
target.truncate()

print "Now I‘m going to ask you for three lines."

line1 = raw_input("line 1:")
line2 = raw_input("line 2:")
line3 = raw_input("line 3:")

print "I‘m going to write these to the file."

target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")

print "Finally, we close it."
target.close()

习题 16: 读写文件