local wLine = "i love you my friend"
    local startPos = 3
    local sX = startPos
    local str = "hate"
    local pre = ""
    if sX > 1 then
        pre = string.sub(wLine,1,sX-1)
    end
    local post = ""
    sX = startPos + string.len(str)
    if sX <= 30 then
        post= string.sub(wLine,sX)
    end
    local newLine = string.sub(pre..str..post,1,30)
    print(newLine)