Using variable named PORT creates issues

[inadarei]

It's a widely established standard for services (e.g. microservices) to consult with the PORT environmental variable on which port to bind to.

The fact that wait-for.sh uses a variable called "PORT" for internal needs gets in the way of this practice and can lead to fatal errors. Since the name of the local variable used for implementing wait-for.sh doesn't really matter, it should be renamed for something less common, e.g. WAIT_PORT

The generic names for HOST and TIMEOUT are less of a problem, possibly but while at it - probably a good idea to namespace them as well.

[NxP4Code]

I had this issue with my node js application. It was using mongo db port to start with and I spent so much time trying to understand why my app is using mongo port to start service. I realized it was due to wait-for script. I change PORT variable name in wait-for script to CHECK_PORT and all worked fine.