awk in 4 steps

What this card says

Why do we need it?

Print a column.

awk '{print $1}' f

What is it?

Set separator.

awk -F, '{print $2}' f.csv

How to do it

Filter rows.

awk '$3>100' f

Example

Sum at END.

awk '{s+=$3}END{print s}' f