1.命令功能rev 按行反向输出文件内容2.语法格式rev file3.使用范例[root@localhost ~]# echo {a..k} >> test [root@localhost ~]# cat test a b c d e f g h i j k [root@localhost ~]# rev test k j i h g f e d c b a [root@localhost ~]# echo {a..k} |rev k j i h g f e d c b a