shell腳本編寫中，if是可以嵌套的，
註意，if條件表達式[]中的空格，以及後面的then就行了
if條件表達式後面的分號“；”可有可無，不影響。

代碼如下

myFile=‘ctr_result.txt‘
if [ -e "$myFile" ]; then
        rm $myFile
        result_code=$?
        if [ "$result_code" -ne 0 ]; then
                echo "[ERROR] when delete $myFile"
                exit $result_code
        fi
        echo "$myFile exists, we delete it"
fi


　　
 

實際shell 腳本

if [ $packetanal_ver != ‘yechang‘ ];then
     packetpid=`ps aux|grep  packetAnal|grep -v "grep"|awk ‘{print $2}‘`

     if [ "$packetpid" ];then
          kill -9 $packetpid
          echo "old packetAnal is killed"
     fi
fi

shell的if嵌套