我的Linux跑了几天，然后登陆上去出现这个：

login as: server
server@18.7.1.2's password:
Last login: Wed Sep 6 09:10:55 2006 from 21.21.12.16
-bash: /bin/hostname: cannot execute binary file
-bash: /bin/grep: cannot execute binary file
-bash: /bin/grep: cannot execute binary file
[server@xx ~]$

然后ps显示：

[server@xx ~]$ ps
-bash: /bin/ps: cannot execute binary file

这个是什么原因？