想让普通用户可以清空内存:echo 1 > /proc/sys/vm/drop_caches;过程:chmod 766 /proc/sys/vm/drop_caches; 报错:chmod: changing permissions of 'xxx': Operation not permitted是因为有比root更高级的用户。lsattr /proc/sys/vm/drop_caches; # 看下他的属性