我们在平常的工作中有时候需要对摸一个文件进行操作,比如在一个文件的每行前面添加##之类的,在shell中这个需求很简单,用sed单行就能搞定,下面我们来看看一个文件:
[root@host-192-168-209-128 py-sed]# cat a.txt this is a text this is use for python this is also user for sed this is a end test file [root@host-192-168-209-128 py-sed]#
用sed的单行命令来搞定这个需求很简单,看下代码:
[root@host-192-168-209-128 py-sed]# sed 's/^/##/g' a.txt ##this is a text ##this is use for python ##this is also user for sed ##this is a end test file [root@host-192-168-209-128 py-sed]#
看看,果然够强大的sed啊,下面我来给大家介绍介绍如何用python实现这个有时候经常需要的操作,直接上代码了:
[root@host-192-168-209-128 py-sed]# cat a.py #!/usr/bin/env python with open('a.txt') as f: con=f.readlines() for i in range(0,len(con)): print "###"+con[i].rstrip('\n')
代码实在很简单,看看效果如何吧:
[root@host-192-168-209-128 py-sed]# python a.py ###this is a text ###this is use for python ###this is also user for sed ###this is a end test file
呵呵,效果出来了吧,但是稍有缺陷,这个需要操作的对象文件我们是写死在代码里面的,如何把文件名作为参数传递给脚本呢,我们需要修改,以实现如下几个功能: 1. 需要把操作的文件作为参数传给脚本 2.需要对操作的对象进行判断,是否存在 3.如果脚本运行错误,需要有友好的提示效果 基于以上的需求,给出代码的最终版本,代码如下:
[root@host-192-168-209-128 py-sed]# cat tou.py #!/usr/bin/env python ''' edit by qhz Email : world77@163.coom This scrip to add "###" at every line for file ''' def usage(): print ''' =============================================== This script to add "###" at every line for file Use Example: python script.py file =============================================== ''' import sys import os if len(sys.argv) == 2: if os.path.isfile(sys.argv[1]): with open(sys.argv[1]) as f: con=f.readlines() for i in range(0,len(con)): print '###'+con[i].strip('\n') else: print "===============================================" print "Your input file name is not exit or not correct" print "Please try again ,bye ..." print "===============================================" else: usage() exit() [root@host-192-168-209-128 py-sed]#
下面来看看各种情况和效果:
[root@host-192-168-209-128 py-sed]# python tou.py =============================================== This script to add "###" at every line for file Use Example: python script.py file =============================================== [root@host-192-168-209-128 py-sed]# python tou.py a.tx =============================================== Your input file name is not exit or not correct Please try again ,bye ... =============================================== [root@host-192-168-209-128 py-sed]# python tou.py a.txt ###this is a text ###this is use for python ###this is also user for sed ###this is a end test file [root@host-192-168-209-128 py-sed]#
好了,这次的python介绍就到这里,我将为大家陆续模拟一些sed的简单功能,希望大家能喜欢