とらりもん - double round brackets Diff

2017/12/27 Ishibashi
!! Let's use double round brackets in Bash, Ubuntu.
◎Most fastest fast and useful way.
COUNT=0
for i in `seq 1 10` ;do
   COUNT=$(( COUNT + 1 ))
   echo for:${i} COUNT:${COUNT}
done

× Using awk command (It is pitiful way) <- I used it previously.
COUNT=0
for i in `seq 1 10` ;do
   COUNT=`echo ${COUNT} |awk '{print $1 + 1}'`
   echo for:${i} COUNT:${COUNT}
done

△ Using expr command.
COUNT=0
for i in `seq 1 10` ;do
   COUNT=`expr $COUNT + 1`
   echo for:${i} COUNT:${COUNT}
done

◯ Using increment
COUNT=0
for i in `seq 1 10` ;do
   (( COUNT++ ))
   echo for:${i} COUNT:${COUNT}
done