The easiest way to learn Linux permissions is from an example. The ls -l command generates a list of contents, such as files along with their permissions. Let’s take a look at the default values for a file called Filename. We are adding spaces to make the output more legible.

Build Your Own Debian/Ubuntu LAMP Server - Quick & Easy Do it Yourself Installation

Apache 2 - Linux Web server
MySQL 5 - MySQL Database Server
PHP4/5 - PHP Scripting Language
phpMyAdmin - Web-based database admin software.

Note: Linux + Apache + MySQL + PHP/Perl together commonly known as LAMP Server.

This short guide shows some important commands for your daily work on the Linux command line.

Simple linux command to search all files in a given path and display the line in the file which matches defined content.
find <PATH> -print | xargs grep "<CONTENT>"
or
find <PATH> -type f -exec grep -H "<CONTENT>" \;