down=50
up=$down+20
cat $i.log | awk 'BEGIN {count = 0} {if ($1 >= $down && $1 < $up) count = count + 1 fi} END {print $down","$up","count}' >> ${i}_result.csv
export变量,然后用 ENVIRON["var"]
((down=50+$j*20))
export down
((up=$down+20))
export up
cat $i.log | awk 'BEGIN {count = 0} {if ($1 >= ENVIRON["down"] && $1 < ENVIRON["up"]) count = count + 1 fi} END {print count}' >> ${i}_result.csv