On MacOSX, I\'m using Packer to build a Vagrant box so I need to continually bring it up and tear it down. I\'m attempting to \'vagrant up\', and receive the standard error
try netstat
netstat -vanp tcp | grep 3000
if your netstat doesn't support -p , use lsof
sudo lsof -i tcp:3000
For Centos 7 use
netstat -vanp --tcp | grep 3000