API - FS

local io = require("io")
local fs = require("filesystem")

function ReadLine(Path, Line)
    local Cur = 0
    if (fs.exists(Path)) then
        for LINE in io.lines(Path) do
            Cur = Cur + 1
            if (Cur == Line) then
                return LINE
            end
        end
    end
    return nil
end

function WriteLine(Path, Line, Content)
    local Lines = {}
    if (fs.exists(Path)) then
        for LINE in io.lines(Path) do
            table.insert(Lines, LINE)
        end
    end
        table.remove(Lines, Line)
        table.insert(Lines, Line, Content)
        local File = fs.open(Path..".tmp", "w")
        for _, LINE in ipairs(Lines) do
            print("Writing: "..LINE)
            File:write(LINE.."\n")
        end
        File:close()
        if (fs.exists(Path)) then
            fs.remove(Path)
        end
        fs.rename(Path..".tmp", Path)
end