运维需求：

遍历/backup203下的文件，凡是等于api_go.log.1...api_go.log.22的迁移到/rotate203

#输入23，迁移1-22的api_go.log.1-22

shuzi = int(raw_input("input your want:"))

for parent,dirnames,filenames in os.walk('/backup203'):

        print filenames

for index,item in enumerate(filenames):

        if filenames[index].startswith('api_go.log.') and int(filenames[index].split('.')[2]) < shuzi:

                print filenames[index]

                str3 = 'mv'+' '+filenames[index]+' '+'/rotate203'

                os.system(str3)

api_go.log.23用.分为3段，每一个都为字符串，最后一个为数字字符串，强转为int型