python file模块 替换输入内容脚本

 root@python-10:/home/liujianzuo/python/test# ls
 passwd  rc.local  test1
 root@python-10:/home/liujianzuo/python/test# py test1 -r EXIT exit /home/liujianzuo/python/test/rc.local
       共修改了0行。
 root@python-10:/home/liujianzuo/python/test# py test1 -r exit EXIT /home/liujianzuo/python/test/rc.local 

 the new line is :
   第 6 行 : # Make sure that the script will "EXIT 0" on success or any other
 the word was replaced is : exit==>EXIT

 the new line is :
   第 16 行 : EXIT 0
 the word was replaced is : exit==>EXIT

       共修改了2行。
 root@python-10:/home/liujianzuo/python/test# cat test1
 #coding:utf-8
 #!/usr/bin/env python

 import sys,os,subprocess
 #a="liujianzuo"
 if len(sys.argv) < 5:
     exit("argc less than 4;like python test.py -r 准备替换的字符 要替换的字符 file_path_name")

 if '-r' in sys.argv:
     ar1=sys.argv.index('-r')
     ar2=sys.argv[ar1+ 1]
     ar3=sys.argv[ar1 + 2]
     filname= sys.argv[ar1 + 3]
 else:
     exit("the first argv must be -r ")
 basedir = "%s/%s"%(os.path.dirname(filname),os.path.basename(filname))
 f=file('%s'%basedir,"r+")
 sum1=0
 numli=0
 while True:
     line=f.readline()
     numli+=1
     #print line
     if ar2 in line:
        # print "now pos+++>",f.tell()
         f.seek(f.tell()-len(line))
         #print f.tell()
         new_line=line.replace(ar2,ar3)
         f.write(new_line)
         print """
 \033[31;1mthe new line is :\033[0m
   第 %s 行 : %s
 the word was replaced is : \033[32;1m%s==>%s\033[0m
         """ % (numli,new_line.strip(),ar2,ar3)
         sum1+=1
         continue
         if line == "":
             print "file is done  bye"
             break
     elif line == "":
         break
 print "\033[33;1m      共修改了%s行。\033[0m"%sum1
 f.close()