[SOLVED] AWK math???

[jms318]

ok im writing a bash script that take the snap shot image of df -k awhile back and compairs df -k now. What i need to report is each drive over 50% full and an mounts that have grown by 5%.

I seem to have the over 50% full down i just cant seem to get awk to work the math out on the $5 $11 fields i need to sub from or take those two and sub them and see if they are greater than 5%. here is my code:

#!/bin/bash
df -k > new.df
paste old.df new.df | tail +2 >both.df
cat both.df | awk '{ if ( $11 > 50 ) print $12,"is over 50 full."}'
cat both.df | awk '{ if ($5 < ($11 - 5)) print $12}'

ive even tried

cat both.df | awk '{ if (($5 - $11) < -5) print $12}'

please if you can show me why this doesnt work?
thanks,
Joseph Swager

[jms318]

I figured out why the math wasn't working cause it could handle it number then % from the df command so i just add a pipe of tr to translate it out and all works like a charm now.