Run once, not again?

I want to create a sort of OS, where I have a setup system that you run manually, and then edits the startup. So far, I have the code for registering, and I need to have it in the same code so I can call upon the variables easily. Is it possible to do something like

if run(1) then
edit("startup", XXXX)

if you want to quickly replace the startup do like this:

function startupReplace(filepath)
if fs.exists("startup") then fs.delete("startup") end
fs.copy(filepath, "startup")
return true
end