# / bin / bash count = 3 while :; do read - p " username: " username echo " input username is $username " if [[ $username != " haha " ]];then #如果输入的不是预定的值则 ((count -- )) #计数器减一 echo " Error! try $count " #显示提示信息 ((count == 0 )) && break || continue #当次数用完的时候则循环结束否则循环继续 else break #当输入正确的时候，跳出循环 fi done
