在awk中计算作为参数传递的算术表达式

awk(1) eval() bc(1)

while read expr; do
    echo "$(($expr))"
done < file

1. expression evaluator from archive.org
2. eval

awk '{system(sprintf("awk \"BEGIN {print " $0 "}\""))}'

$(( ))

perl -nE 'say eval'

iftop

Host name                   last 2s   last 10s   last 40s cumulative

   1 10.150.1.1      =>     650B      533B        533B     2.08KB
     85.239.108.20   <=     16.0KB    12.9KB     12.9KB   51.5KB

iftop -i eth1 -ts 10 -Bn|egrep "<|>"| sed 's/^   //g;s/^[1-9]/x/g;s/KB/ 1024/g;s/B/ 1/g' | tr -d '\n'|tr "x" '\n'| grep .| awk '{print $1" "$11" - "$9*$10+$19*$20" "$9*$10" "$19*$20 }'