Knowing virtual memory statistics in linux

To know about your system`s virtual memory statistics, type 

$ vmstat    #print statistics with header 

To check continiously type : 

$ vmstat [-n] [delay [ count]]   #don`t give brackets  

 eg.  

$ vmstat -n 1 10   #this will print statistics for 10 times with 1 sec delay  

Command options:

 usage: vmstat [-V] [-n] [delay [count]]
              -V prints version.
              -n causes the headers not to be reprinted regularly.
              -a  print inactive/active page stats.
              -d  prints disk statistics
              -D prints disk table
              -p  prints disk partition statistics
              -s   prints vm table
              -m prints slabinfo
              -S  unit size