Find PID listening specific port

To find which process is listening a specific port, the 3 options below can be used.

netstat -alnp | grep ::80

or

fuser -v 80/tcp

or

lsof -nPi tcp:80

Quit ssh with out killing running process

Since I need to keep start.jar of jetty running on EC2. I need to quit the ssh without killing the current running jetty process. There is a tool called "screen" can do this easily.

Follow the steps below
1.

screen

2.

sudo java -jar start.jar

3.

ctrl+a and then ctrl+d

4.quit ssh.

Sudo xxx complaining command not found

Problem:
Just installed doctrine. I found if I use command "doctrine" straight away it works but not working with sudo. When I typed in

sudo doctrine

it complains

sudo: doctrine: Command not found

Then I tried to use full path of doctrine with sudo which worked. So I think this should be caused by that sudo command does not use the personal path environment.

Using full qualified path every time is annoying.

Solved:
Create a file at

~/.bash_aliases 

with content

alias sudo='sudo env PATH=$PATH $@'

Logout and login again.

Apache Virtual Hosts - permissions

See this article
https://articles.slicehost.com/2007/9/18/apache-virtual-hosts-permissions