#!/usr/local/bin/awk -f

BEGIN { 
  size = 10
  n    = 0 
}

{ 
  line[n] = $0
  n = (n+1)% size
}

END{
  if(NR<=size) 
    for(i=0; i<size; i++) print line[i]
  else
    for(i=0; i<size; i++) print line[(i+n)%size]
}