React start set port number from CLI

Question

I'm attempting to start my react server through linux CLI with a specified port number. I am NOT asking about changing the package.json script to include a defined port number.

I need to be able to start multiple react instances with different ports through CLI.

I have seen recommendations such as

npm start --PORT=4000, npm start --PORT 4000, npm start -- --PORT=4000

Of which none work, they all set the port to the default of 3000, or if I have a defined port in the package.json such as 5000, it defaults to that.

Whats the correct command for setting the port through CLI?

try PORT=4000 npm start

Tom Berghuis
– Tom Berghuis

2019-04-22 04:11:24 +00:00
Commented Apr 22, 2019 at 4:11 — Tom Berghuis
– Tom Berghuis, Commented Apr 22, 2019 at 4:11

Syafrizal Akhzan · Accepted Answer · 2019-04-22 05:05:16Z

3

you can do it by adding PORT=4000 before react-scripts start in package.json.

"scripts": {
   "start": "PORT=4000 react-scripts start"
}

then you can execute npm start

answered Apr 22, 2019 at 5:05

Syafrizal Akhzan

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Comments

yekanchi · Accepted Answer · 2019-04-22 04:12:43Z

2

It's actually an environment variable for the port, so you can specify a PORT environment variable beforenpm start

export PORT=3005; npm start #For Linux
$env:PORT=3005; npm start #For Powershell

answered Apr 22, 2019 at 4:12

yekanchi

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