LINK:https://www.snbforums.com/threads/spdmerlin-automated-speedtests-with-graphs.55904/

v2.0.0
Updated 2019-07-08

This script uses a large amount of RAM/memory when the speedtest is running, and as such a swap file is required

The speedtest is scheduled to run at 12 past and 42 past the hour, every hour, by default

Regarding speeds not necessarily matching browser-based tests, please see https://github.com/sivel/speedtest-cli#inconsistency 

Run automated speedtests for your Internet on your router with graphs available on the Tools page of the WebUI.

This script serves as a user-friendly installer for a personal project developed by @JGrana
Permission received from @JGrana to publish this!

spdMerlin is free to use under the GNU General Public License version 3 (GPL 3.0).

spdMerlin uses speedtest-cli

This project is hosted on GitHub

Love the script and want to support future development? Any and all donations gratefully received! PayPal donation

Supported Models
Models
All modes supported by Asuswrt-Merlin. Models confirmed to work are below:

• RT-AC68U

• RT-AC86U

• RT-AC3100

Firmware versions
You must be running firmware no earlier than 384.XX Asuswrt-Merlin

Installation
Using your preferred SSH client/terminal, copy and paste the following command, then press Enter:

/usr/sbin/curl --retry 3 "https://raw.githubusercontent.com/jackyaz/spdMerlin/master/spdmerlin.sh" -o "/jffs/scripts/spdmerlin" && chmod 0755 /jffs/scripts/spdmerlin && /jffs/scripts/spdmerlin install

Usage
To launch the spdMerlin menu after installation, use:

spdmerlin

If this does not work, you will need to use the full path:

/jffs/scripts/spdmerlin

Updating
Launch spdmerlin and select option u