# Unix Unix is a family of multitasking, multi-user operating systems that originated at AT&T's Bell Labs in 1969. Developed by [[Ken Thompson]], [[Dennis Ritchie]], and others, Unix introduced concepts that remain foundational to modern computing: hierarchical file systems, plain text configuration, pipes, and the philosophy of small, composable tools. Dennis Ritchie rewrote Unix in C (1973), making it one of the first portable operating systems. Due to AT&T's licensing restrictions, Unix spawned numerous variants and inspired free alternatives. BSD emerged from Berkeley in the 1970s-80s, while [[Richard Stallman]]'s [[GNU is not Unix (GNU)|GNU]] project (1983) and [[Linus Torvalds]]' [[Linux]] kernel (1991) created the dominant free Unix-like systems used today. The [[POSIX]] standard (1988) codified Unix interfaces for portability. ## Unix Philosophy The Unix philosophy, articulated by Doug McIlroy, emphasizes: - **Do one thing well**: Programs should have a single, focused purpose - **Text streams**: Use plain text as the universal interface - **Composability**: Small tools combined via pipes and scripts - **Prototyping**: Build quickly, iterate, refine - **Simplicity**: Prefer clarity over cleverness ## Key Innovations | Innovation | Impact | |------------|--------| | Hierarchical filesystem | Everything is a file under / | | Pipes | Connect program output to input | | Shell | Programmable command interpreter | | C language | Portable systems programming | | Plain text config | Human-readable configuration | | Multi-user | Process isolation, permissions | ## Unix Family Tree - **AT&T Unix**: Original (System III, System V) - **BSD**: Berkeley Software Distribution (FreeBSD, OpenBSD, NetBSD) - **Commercial**: Solaris, AIX, HP-UX - **Unix-like**: [[Linux]], [[GNU is not Unix (GNU)|GNU]]/Linux, macOS (Darwin/XNU) ## Notable Figures - **Ken Thompson**: Co-creator of Unix, UTF-8, Go - **Dennis Ritchie**: Co-creator of Unix, creator of C - **Brian Kernighan**: Contributed to Unix, co-authored K&R C - **Doug McIlroy**: Invented Unix pipes, articulated Unix philosophy ## References - https://en.wikipedia.org/wiki/Unix - https://en.wikipedia.org/wiki/Unix_philosophy - *The Unix Programming Environment* by Kernighan & Pike ## Related - [[GNU is not Unix (GNU)]] - [[Linux]] - [[POSIX]] - [[Bash]] - [[Free and Open Source Software (FOSS)]] - [[Richard Stallman]] - [[Linus Torvalds]] - [[Ken Thompson]] - [[Dennis Ritchie]]