指定文件夾，指定文件類型，替換該文件夾下全部文件的內容。

注意在window下的讀寫內容需要指定編碼，還需要在文件頭指定#coding:utf-8 編碼，避免出現編碼問題。

代碼如下:
#coding:utf-8
import os
import os.path

path='.'
oldStr='.php'
newStr='.html'

for (dirpath, dirnames, filenames) in os.walk(path):
    for file in filenames:
        if os.path.splitext(file)[1]=='.html':
            print(file)
            filepath=os.path.join(dirpath,file)
            try:
                text_file = open(filepath, "r")
                lines = text_file.readlines()
                text_file.close()
                output  = open(filepath,'w',encoding= 'utf-8')
                for line in lines:
                    #print(line)
                    if not line:
                        break
                    if(oldStr in line):
                        tmp = line.split(oldStr)
                        temp = tmp[0] + newStr + tmp[1]
                        output.write(temp)
                    else:
                        output.write(line)
                output.close()
            except Exception:
                print(Exception)
                break