marquee

local function scroll(str,maxlen)
    str=str:sub(-1,-1)==" " and str or str.." "
    local scrolled=0
    while true do
        scrolled=scrolled%#str+1
        term.setCursorPos(1,1)
        write(str:rep(math.ceil((maxlen+scrolled)/str:len())):sub(scrolled,maxlen+scrolled))
        sleep(0.1)
    end
end

scroll("hello, this is a test",10)