vmstat

Shell Programming and Scripting
1

Hi

I need to write a script to display VMSTAT every 5 seconds and I just need the memory columns - swap free re and just the numbers and the headers arent required.

For example

bash-3.00$ vmstat 5| awk '{print $4" "$5" "$6}'
disk faults cpu ------ This header isnt required
swap free re ------ This header isnt required
36889520 7061456 11

Also I need to append the output of this comman in a file after every 5 seconds

2

you can try running it directly

nohup vmstat 5| awk '{print $4" "$5" "$6}' > file &
3 
while :
do
 vmstat | awk '{print $4" "$5" "$6}' | tail +3 >> stats.log
 sleep 5
done
4

Beware that the first line of statistics from vmstat are garbage.
Therefor anchal_khare post will not produce valid results.

Also beware that "vmstat 5" will not stop until it is interrupted or killed.
To get meaningful statistics from vmstat it must be run with at least two iterations:

vmstat 5 2

Then take the statistics from the last line output.
A 5-second snapshot of a unix system would be biased by vmstat itself.

In practice you get a more meaningful statistics from say:

vmstat 30 2

run every 20 mins.