How to update environment variable in shopify application?

[mrkarim]

Hello Developers, 

I am trying to build an application and I am unable to update APP_URL link from the env variable.It always shows some randomly generated link. Is there any way to update it?

[btrain-004]

It depends on how you are starting up your environment. But this is how I did it while in dev mode using Shopify 3.0 CLI for node, you can pass in the "--tunnel-url" and the URL you want. 

--tunnel-url doc for Shopify node.