How to instll nginx on buntu

My machine OS version is ubuntu Server 14.04 LTS

Setting repository and install.

sudo -s
nginx=stable # use nginx=development for latest development version
add-apt-repository ppa:nginx/$nginx
apt-get update
apt-get install nginx

ERROR

if you machine return error like this.

add-apt-repository: command not found

You must install apt plugin before you can add repository.

sudo apt-get install software-properties-common

Reference document:

Nginx wiki