“Everything is a file” describes one of the defining features of Unix, and its derivatives — that a wide range of input/output resources such as documents, directories, hard-drives, modems, keyboards, printers and even some inter-process and network communications are simple streams of bytes exposed through the filesystem name space.

The advantage of this approach is that the same set of tools, utilities and APIs can be used on a wide range or resources. There are a number of file types. When a file is opened a file descriptor is created. The file path becoming the addressing system and the file descriptor being the byte stream I/O interface. But file descriptors are also created for things like anonymous pipes and network sockets via different methods. So it is more accurate to say “Everything is a file descriptor”.

— Wikipedia on Everything is a file

2012.06.11 Monday ACHK