python备份文件示例代码

#-*- coding:utf-8 -*- 
import sys,os,shutil,filecmp 
 
MAXVERSIONS = 100 
 
def backup(tree_top, bakdir_name="bakdir"): 
    for dir,subdirs,files in os.walk(tree_top): 
        #确保每个目录都有一个备份目录 
        backup_dir = os.path.join(dir,bakdir_name) 
        if not os.path.exists(backup_dir): 
            os.makedirs(backup_dir) 
        #停止对备份目录的递归 
        subdirs[:] = [d for d in subdirs if d != bakdir_name] 
        for file in files: 
            filepath = os.path.join(dir,file) 
            destpath = os.path.join(backup_dir,file) 
            #检查以前的版本是否存在 
            for index in xrange(MAXVERSIONS): 
                backfile = '%s.%2.2d' % (destpath, index) 
                if not os.path.exists(backfile): 
                    break 
        if index > 0: 
            old_backup = '%s.%2.2d' % (destpath,index-1) 
            abspath = os.path.abspath(filepath) 
            try: 
                if os.path.isfile(old_backup) and filecmp.cmp(abspath, old_backup,shallow=False): 
                    continue 
            except OSError: 
                pass 
        try: 
            shutil.copy(filepath,backfile) 
        except OSError: 
            pass 
 
if __name__ == '__main__': 
    try: 
        tree_top = sys.argv[1] 
    except IndexError: 
        tree_top = '.' 
    backup(tree_top) 
 

for file in files: 
    name,ext = os.path.splitext(file) 
    if ext not in ('.py','.txt','.doc'): 
        continue 
 

subdirs[:] = [d for d in subdirs if d != bakdir_name]