[root@NB ok]# echo chenlin|base64;echo
Y2hlbmxpbgo=

[root@NB ok]# yum search iotop
Loaded plugins: fastestmirror, refresh-packagekit, security
Loading mirror speeds from cached hostfile
 * base: mirrors.btte.net
 * extras: mirrors.btte.net
 * updates: mirrors.tuna.tsinghua.edu.cn
============================== N/S Matched: iotop ==============================
iotop.noarch : Top like utility for I/O

  Name and summary matches only, use "search all" for everything.
[root@NB ok]# yum install iotop