using awk im trying to print $4 to the the begining of the line the code below prints it above the line the string is random so cant use string name

awk -F"[--]" '{print $4 ;print$0}' file 

i have

/example-origin-live/ngrp:tennis-320-fd1d9b92-69e2-446c-a3e6-45b33a55efc9 

with code above i get

320 /example-origin-live/ngrp:tennis-320-fd1d9b92-69e2-446c-a3e6-45b33a55efc9 

needed

320/example-origin-live/ngrp:tennis-320-fd1d9b92-69e2-446c-a3e6-45b33a55efc9 

thanks for help