rev 按行反向输出文件内容
rev file
[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
原文：https://www.cnblogs.com/joechu/p/8947814.html