python学习：简单的wc命令实现

#!/usr/bin/python

 

import sys

import os

 

try:

    fn = sys.argv[1]

except IndexError:

    print "please follow a argument at %s" % __file__

    sys.exit()

if not os.path.exists(fn):

    print "%s is not exists" % fn

    sys.exit()

fd = open(sys.argv[1])

data = fd.read()

chars = len(data)

words = len(data.split())

lines = data.count(' ')

 

print "%(lines)s %(words)s %(chars)s" % locals()

 

[root@web10 day1]# python 8_argv.py /etc/hosts

4 14 219

 

用 sys.argv 表示脚本的第一个参数 从文件读取实现wc命令