Find and Kill Process on Port 3000

I was running into an issue running my React app locally where the default port was previously used and unreleased.

❯ yarn dev
yarn run v1.22.10


Port 3000 is already in use.

You may also see a similar EADDRINUSE error if a node processes is trying to use an occupied port:

Error: listen EADDRINUSE: address already in use :::3000

Solution

We can find and kill the process running on port tcp:3000 with the command:

(I am running macOS Big Sur 11.4).

$ lsof -t -i tcp:3000 | xargs kill

• lsof: List open files
• -t: Terse output with process identifiers only (output can be piped)
• i: Selects the listing of files where the address matches
• tcp:3000: The address at TCP port 3000
• |: Pipe the output on the left to the command on the right
• xargs: Build and execute lines
• kill: Kill a process by PID