自己写的一个小函数，用来备份文件的。使用的时候用. ./载入就可以了。命令是backup -d -s，-d指定目录，-s指定后缀，默认为当前日期。可以备份多个文件-Write a small function, used to back up files. When used with ../load on it. Command is backup-d-s-d specified directory-s suffix is ​ ​ specified, the default to the current date. You can back up multiple file