linux free命令

linux下free命令用于查看系统内存使用情况：

[frank@localhost ~]$ free
             total       used       free     shared    buffers     cached
Mem:       1914492    1131236     783256          0      67636     724244
-/+ buffers/cache:     339356    1575136
Swap:      1048568          0    1048568

其中，total表示系统内存总量，used表示已经使用的内存总量，free表示剩余的内存总量，

A buffer is something that has yet to be "written" to disk. 

A cache is something that has been "read" from the disk and stored for later use.

可以使用命令：echo 3 > /proc/sys/vm/drop_caches释放掉被系统cache占用的数据。