Vi is a text editor found in most UNIX environments. What is normally installed is a program called vim, which stands for vi improved. You can start vi (or vim) by typing vi at the UNIX command prompt.
CentOS is an Enterprise Linux distribution based on the freely available sources from Red Hat Enterprise Linux. Each CentOS version is supported for 7 years (by means of security updates). A new CentOS version is released every 2 years and each CentOS version is regularly updated (every 6 months) to support newer hardware. This results in a secure, low-maintenance, reliable, predictable and reproducible Linux environment.
This page provides steps to install CentOS Linux in preparation for installation and setup of an apache web server, mysql database server, tomcat server, or other service.