Awk command - calculation of columns

Question

I am very new in Awk. I want to calculate the difference between first row column2 and second row column2. For instance:

Num1 Num2 
23   26
34   39
43   58
63           


        

Answer 1

Remember the old values (from the previous row).

awk 'NR > 1 { print $1 - old1, $2 - old2 }
            { old1 = $1; old2 = $2 }' data.file

Answer 2

You can try this,

awk 'NR==1{col1=$1; col2=$2;} { print $1-col1,$2-col2; col1=$1;col2=$2}' yourfile