About the script writing

[Mark Grant]

Actually, the thing I just posted above assumes you are starting with your original system1.txt
file, not just those four numbers.

[eric_204]

thx Mark, my second requirement is paste the numbers to the third column , could suggest how to do it ? thx.

[Mark Grant]

Hi eric,

I think you just need to have an appropriate number of spaces before the $a in this bit

echo "<-spaces-> $a"

Unless I am misunderstanding you.