Clearing only selected lines?

I want to make a program that will only clear the 4th and 5th lines.
term.clear() clears everything, so I'm guessing that there's something that you put in the "()"s?

You can just go to the line with term.setCursorPos(), then use term.clearLine().

term.setCursorPos(1,4)
term.clearLine()
term.setCursorPos(1,5)
term.clearLine()

Or make a function to clear a specific line which I use in my programs.

function clrLine(y)
    cX, cY = term.getCursorPos()
    term.setCursorPos(1,y)
    term.clearLine()
    term.setCursorPos(cX, cY)
end

The getting cursor position and setting it back to it is only if you need that, I just added it now but I don't use it.