Update October 2020: These were tested to work with Ubuntu 20.x.
You want to install the four core components that compose the LAPP stack. That is you want to install Apache, Postgres and PHP on Ubuntu Linux (which comes with Perl pre-installed). How do you do this?
1. Install Ubuntu. If you need directions, see this link.
2. Run this command:
sudo apt-get -y install php apache2-bin postgresql postgresql-contrib php-pgsql libapache2-mod-php
# Please note that the postgresql-contrib is an optional package.
3. You are done. You can enter the PostgreSQL command line with this command:
sudo -u postgres -i
You may also want to see these relevant postings:
How Do You Deploy LAPP with Frontend User Authentication?
How Can You Accept User Input with PHP and Use It in a SQL Command?