"The major design factors behind UNIX were to create an operating system and supporting software that were simple, elegant, and easy to use. Elegant, in this contect, generally means good programming style and thrifty memory management. These design characteristics led to the following maxims among UNIX builders:

1. Make each program do one thing well. These simple programs often are called tools.
2. Expect the output of every program to become the input to another, yet unknown, program. This means that simple tools can be connected to do complex jobs.
3. Don't test hesitate to build new programs to do a job. The library of tools keeps increasing."