I want to run a shell script on one of my Linux instances.
I need the ability wherein I can invoke this script over a HTTP call.
Came across an app which enables this (built.io flow). Can someone guide me to set up connection to my server and get this running?
As far as i understand your question, you want to do ssh in your remote machine using Built.io Flow.
for this you have to create flow in your Built.io Flow account and use SSH activity in it and then execute flow using webhook.
Its easy to use, please refer these links for more info
https://flowdocs.built.io/activity/devops-tools/SSH-Commander
https://flowdocs.built.io/connection/ssh