function login()
 local un,pw,cc = "","",false
 print(MOTD)
 if #os.users() > 0 then
  repeat
   io.write(net.id.." login: ")
   un = io.read()
   io.write("Password: ")
   pw = io.read("*")
   cc = os.su(un,pw)
  until cc
  return true
 end
end
function loginmanager(sI)
 spawn("login manager: "..sI or os.getenv("sI"), function()
 if sI then os.setenv("sI",sI) end
 while true do
  login()
  local _,nshell = pcall(loadfile,os.getuattr(os.getuid(),"shell"))
  if type(nshell) ~= "function" then nshell = shell end
  pcall(nshell,sI)
  print(" ")
 end
end) end