startup:3: attempt to concatenate string and nil

function DrawBackground()
term.setCursorPos(1,1)
local termw, termh = term.getSize() -- I know that 51 * 19 is 969, but for example I'm using CC with a terminal size of 80 * 25
-- you can delete the line above if you put it at the beginning of the program

term.setBackgroundColor(colors.blue) -- it's enough to set the color once
term.setTextColor(colors.blue)
for i = 1, termw * termh do
  write("G")
end
end

function DrawBackground()
term.setCursorPos(1,1)
for i = 1,969 do
  term.setBackgroundColor(colors.blue)
  term.setTextColor(colors.blue)
  write("G")
end
end

local termw, termh = term.getSize() -- I know that 51 * 19 is 969, but for example I'm using CC with a terminal size of 80 * 25
-- you can delete the line above if you put it at the beginning of the program
local textLeft = "Login"
local textRight = "SteamPunkOS"
print(textLeft..string.rep(" ", termw - #textLeft - #textRight)..textRight)

print("Login								   SteamPunkOS")

os.pullEventTerminatable = os.pullEvent
os.pullEvent = os.pullEventRaw