rails s 不能开启，提示已经开启

** 是 ctrl-c，不是 ctrl-z，在重开 rails server 的时候 **

$rails s

=> Booting Puma

=> Rails 5.0.0 application starting in development on http://localhost:3000

=> Run `rails server -h` for more startup options

A server is already running. Check /Users/lvchengbo/job-listing/tmp/pids/server.pid.

Exiting

解决办法

https://stackoverflow.com/questions/24627701/a-server-is-already-running-check-tmp-pids-server-pid-exiting-rails

运行命令

kill -9 $(lsof -i tcp:3000 -t)