Upon my journey to master Unix/Linux, I came across this saying and some of its derivaties:
Everything is a file.
Everything in Unix is a file.
Reflecting upon my humble knowledge of Unix/Linux, I think this phrase concisely defines a very foundational idea of the Unix/Linux system.
As such, I would like to use this quote in my up-coming presentation on Linux introduction. For that purpose, I need to know the history behind this quote with reference.