vmstat

Vmstat

vmstat reports virtual memory statistics. The following are some of vmstat command examples.

vmstat by default will display the memory usage (including swap) as shown below.

$ vmstat
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0 305416 260688  29160 2356920    2    2     4     1    0    0  6  1 92  2  0

To execute vmstat every 2 seconds for 10 times, do the following. After executing 10 times, it will stop automatically.
$ vmstat 2 10
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 1  0      0 537144 182736 6789320    0    0     0     0    1    1  0  0 100  0  0
 0  0      0 537004 182736 6789320    0    0     0     0   50   32  0  0 100  0  0
..

iostat and vmstat are part of the sar utility. You should install sysstat package to get iostat and vmstat working.