CentOS Linux top htop and release memory cache

top 可查看 CPU, RAM, disk I/O 狀況。htop 多了可以查看 memory cache 的功能。

htop download link:
http://pkgs.repoforge.org/htop/

Release memory cache command:
echo 3 > /proc/sys/vm/drop_caches

Reference:
http://maxding.blogspot.tw/2010/10/centos-htop.html
http://blog.jsdan.com/3131