I want to show how to quickly and reliably troubleshoot a network using notepad++.
If you are not using Cisco GENIE and your network is not very big and you have several routers/switches only.
For illustration, I created a simple topology.

First, the loopback interface of the router 1 can ping the loopback interface of the router 3 and it is a base state.
I created a series of commands to check the status of the network script.txt
and saved the result as text result1.txt
But then someone mistakenly turned off the router 3 loopback interface
and the connection is gone.
How to quickly find a malfunction?
In the event of a malfunction, re-run the commands and compare the text results in notepad++ and see marked with red

We immediately see where the problem is.
This method can also be used for palo-alto and ASA to see configuration changes
because it’s hard to remember many web pages and find the difference on many web pages.
This method, unlike Cisco GENIE, can be used for voice and security.