练习_while_until

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#!/usr/bin/bash i=2 while [ $i -lt 25 ] do         {                 ip=192.168.201.129                 ping -c1 -W1 $ip &>/dev/null                 if [ $? -eq 0 ];then                         echo "$ip up "                 fi         }&         let i++ done wait echo "all finish..."

　

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#!/usr/bin/bash i=2   until [ $i -gt 100 ] do         let sum+=$i;         let i++ done   echo "sum：$sum"