Files and Processes

Just like any other operating system, everything in UNIX is either a file or a process.

File is a collection of data. Files can be created by the users using the text editors.

A process is an executing program identified by a unique PID (process identifier).

Examples of files:

• a document (letter, report, notes etc.)
• program written in some high-level programming language.
• instructions understandable by the machine and not to the general user, for example, a binary file).
• a directory, containing information about its contents, which may contain subdirectories and files.