function on_msg_receive (msg)
    if started == 0 then
        return
    end
    if msg.out then
        return
    end

    --Damit der "Gelesen Haken" erscheint
    if msg.text then
        mark_read (msg.from.print_name, ok_cb, false)
    end

    --Ggf. nur eine Rufnummer zulassen:
    if msg.from.print_name ~= 'Kontakt_Name' then
        os.execute("/home/pi/tg/send_script " .. msg.from.print_name .. " 'Ungueltige Nr.'")
        return
    end
    if (string.lower(msg.text) == 'uptime') then
        local handle = io.popen("sudo python /home/pi/tg/tg_actions.py uptime")
        local res = handle:read("*a")
        handle:close()
        os.execute("/home/pi/tg/send_script ".. msg.from.print_name .." '"..res.."' ")
        --Alternativ:
        --send_msg (msg.from.print_name, res)
        return
    elseif (string.lower(msg.text) == 'shutdown') then
        local handle = io.popen("sudo python /home/pi/tg/tg_actions.py shutdown")
        local res = handle:read("*a")
        os.execute("/home/pi/tg/send_script "..msg.from.print_name.." '"..res.."' ")
        handle:close()
        return
    elseif (string.lower(msg.text) == 'reboot') then
        local handle = io.popen("sudo python /home/pi/tg/tg_actions.py reboot")
        local res = handle:read("*a")
        handle:close()
        os.execute("/home/pi/tg/send_script ".. msg.from.print_name .." '"..res.."' ")
        return
    else
        os.execute("/home/pi/tg/send_script ".. msg.from.print_name .." 'Fehler' ")
    end

end