How to run 2 or more servers on node with one command?

Question

Command line

There are 3 servers in 3 different folders.
How can a command run all 3 of them, and not go into each one in turn and write npm run start?

Answer 1

https://pm2.keymetrics.io/

Answer 2

Write a shell script consisting of three launch commands and run it with one command

Answer 3

npm-run-all package to use