--put these all in folder 'os' (mkdir os)
--make this as .menu
local w,h = term.getSize()
function clearColor()
    setBackgroundColor(colors.black)
end
function printCentered (y,s)
    local x = math.floor((w- string.len(s)) / 2)
    term.setCursorPos(x,y)
    term.clearLine()
    term.write(s)
end
local nOption = 1
mon.write("Penguin OS 1.1 Running...")
local function drawMenu()
    term.clear()
    setCursorPos(1,1)
    term.write("Penguin OS 1.1")
    setCursorPos(1,2)
    term.write("New Features: GUI Updates; Programs option runs an error screen")
    setCursorPos(1,3)
    term.write("because Programs function not yet finished{}")
    setCursorPos(1,4)
    term.write("Report any bugs to Penguinboy887")
    term.setCursorPos(w-11, 1)
    if nOption == 1 then
        term.write("Go to Command Prompt")
    elseif nOption == 2 then
        term.write("List Executable Programs")
    elseif nOption == 3 then
        term.write("Shut the Computer off")
    elseif nOption == 4 then
        term.write("Uninstall")
else
end
local function drawFrontend()
printCentered(math.floor(h/2) - 3, "----")
printCentered(math.floor(h/2) - 2, "Menu")
printCentered(math.floor(h/2) - 1, "----")
printCentered(math.floor(h/2) - 0, ((nOption == 1) and "--{Command}--", or "|Command|")
printCentered(math.floor(h/2) + 1, ((nOption == 2) and "--{Programs}--", or "|Programs|")
printCentered(math.floor(h/2) + 2, ((nOption == 3) and "--{Shutdown}--", or "|Shutdown|")
printCentered(math.floor(h/2) + 3, ((nOption == 4) and "--{Uninstall}--", or "|Uninstall|")
end
setBackgroundColor(colors.green)
drawMenu()
drawFrontend()
while true do
    e,p = os.pullEvent()
    if e == "key" then
        local key = p
        if key == 17 or key == 200 then
            if nOption > 1 then
                nOption = nOption - 1
                drawMenu()
                drawFrontend()
            end
        elseif key == 28 or key == 208 then
            if nOption < 4 then
                nOption = nOption + 1
                drawMenu()
                drawFrontend()
            end
        elseif key = 28 then
            break
        end
    end
end
term.clear()
if nOption == 1 then
    shell.run("os/.command")
elseif nOption == 2 then
    shell.run("os/.programs")
elseif nOption == 3 then
    os.shutdown()
else
    shell.run("os/.uninstall")
end