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double round brackets

2017/12/27 Ishibashi

Let's use double round brackets in Bash, Ubuntu.

◎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
Last modified:2017/12/29 19:43:08
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