Philosophy
Linux follows five core principles:
Everything is a file
All configuration files for the various services running on the Linux OS are stored in one ore more text files.
Small, single-purpose programs
Linux tools can be combined to work together. Each tool should perform only one task and should do it well.
Ability to chain programs together to perform complex tasks
The integration and combination of different tools enable us to carry out many large nad complex tasks, such as processing or filtering specific data results.
Avoid captive user interfaces
Linux is designed to work mainly with the shell/terminal, which gives the user greater control over the operating system and decision over which GUI to use (if any).
Configuration data stored in a text file
An example of such a file is the /etc/passwd file.