＞第 31 章 Shell脚本＞Shell脚本语法＞while/do/done＞习题

#! /bin/sh

COUNTER=1
echo "Enter password:"
read TRY
while [ "$TRY" != "secret" -a $COUNTER -lt 5 ]
do
  echo "Sorry, try again"
  COUNTER=$(($COUNTER+1))
  read TRY
done

#! /bin/sh

COUNTER=1
echo "Enter password:"
read TRY
while [ "$TRY" != "secret" ]; do
  if [ $COUNTER -lt 5 ]; then
    echo "Sorry, try again"
    COUNTER=$(($COUNTER+1))
    read TRY
  else
    echo "ERROR!"
    exit 1
  fi
done
echo "hello world"

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