How to fix it when the Rails Server is already running, but not where you can find it

Have you ever accidentally closed a terminal tab while the rails server was still running and weren’t able to find it again?

I’ve done this a couple of times and couldn’t quite find the answer before. This meant the only way out was restarting my machine. Ug. I really dislike doing that. But today, when I overflowed my server stack and accidentally closed the window (yikes), I was able to find an answer – at last!

The sad, sad message when I tried to start rails s again:

A server is already running. Check /Users/my_computer_name/your_project_location/tmp/pids/server.pid.
Exiting

On OSX, you can run this:

sudo lsof -iTCP -sTCP:LISTEN -P | grep :3000

You’ll either get nothing back (which means no server is running) OR something like this (which is what I got):

ruby      56134 computer_name   11u  IPv4 0xe3ccaa0e8651f54d      0t0  TCP :3000 (LISTEN)

Grab that number (in my case 56134) and killll it:

kill -9 56134

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