shell 正则匹配

if [[ "abcyyy13554221547HelloxxxWorld" =~ yyy([0-9]{11})(Hello)xxx(.*) ]]
 then
         echo The regex matches!
         echo $BASH_REMATCH       
         echo ${BASH_REMATCH[1]}  
         echo ${BASH_REMATCH[2]}
         echo ${BASH_REMATCH[3]}  
 fi

The regex matches!
yyy13554221547HelloxxxWorld
13554221547
Hello
World