for i in `seq  `   #seq 生成从1到10  如果生成从10到1则写作 seq 10 -1 1

   do

      echo $i

 done

for i in where is a will there is a way

   do

      echo "word:$i"

done

 for (( i=;i<;i++ )) #2个小括号是为了做运算

   do

       echo $i

 done

for ((;;))

  do

     ping -c1 $ &>/dev/null

     if [ $? -eq  ]

        then

            echo -e "`date +"%F %H:%M:%S"` : $1 is \033[32m UP \033[0m"

        else

            echo -e "`date +"%F %H:%M:%S"` : $1 is \033[31m Down \033[0m"

        fi

     sleep

done