# 用 Python 實現類似 grep 的功能
## 問題
一個草圖：
![图片描述][1]
現實現在文件夾和子文件夾下查找目標字串，
但不知如何提取包含目標字符的字串，並寫入到新文件中。
[1]: https://segmentfault.com/img/bVyX2e
```python
#!/usr/bin/env python
#-*- coding:utf-8 -*-
import os, sys
import fnmatch
listonly = False
skipexts = ['.js']
def visitfile(fname,searchkey):
global fcount,vcount
try:
if not listonly:
if os.path.splitext(fname)[1] in skipexts:
if open(fname).read().find(searchkey) != -1:
print '%s has %s '%(fname,searchkey)
fcount+=1
except: pass
vcount +=1
def visitor(args,directoryName,filesInDirectory):
for fname in filesInDirectory:
# 返回文件所在路径和文件名
fpath = os.path.join(directoryName,fname)
if not os.path.isdir(fpath):
visitfile(fpath,args)
def searcher(startdir,searchkey):
global fcount,vcount
fcount = vcount = 0
os.path.walk(startdir,visitor,searchkey)
if __name__=='__main__':
# root=raw_input("type root directory:")
root = '/home/jiangbin/findJS'
key=raw_input("type key:")
searcher(root,key)
print 'Found in %d files,visited %d'%(fcount,vco
