bind. address already in use

If you've been developing with Postgres locally, you've probably run into this annoying error:

failed to bind port 0.0.0.0:5432/tcp: bind: address already in use

How I've been solving this problem in the past is by using lsof to find the PID of the process that's using the port.

Then, I can kill the process using the PID. You might need to run this command as root.

lsof -i tcp:5432

This will show you the PID of the process that's using the port.

kill -9 <PID>

Now, you can run your Postgres server again.

It works, but I recently learned you could shorten it to one command:

lsof -ti :5432 | xargs kill -9

What's happening here?

• You don't need to specify the tcp protocol, because it's the default.
• The additional -t option makes lsof return just the PID.
• The | xargs part uses the pipe operator to pass the output of lsof to xargs.
• xargs kill -9 reads the PIDs and builds a single command to terminate the processes.

PS. This’ll nuke any process on whatever port you provide without asking questions, so double-check what’s running before you pull the trigger.