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
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