BSDstyle

BSDstyle is a historical set of coding conventions used by the Berkeley Software Distribution (BSD) family of operating systems for C code and shell scripts. It is not a formal standard but a collection of practices that evolved within FreeBSD, NetBSD, OpenBSD and related projects to encourage readability, consistency, and maintainability across large code bases.

Originating from early C programming norms at Berkeley, BSDstyle has been codified in project guides and widely adopted by developers working on BSD-derived software. It has influenced, and been influenced by, other style traditions in the open-source community and remains a reference point in discussions of Unix-like system code.

Common features include brace placement on the same line as control statements (the one-true-brace style), consistent indentation using the project’s preferred method (traditionally tab-based indentation), clear separation of header and source files, and use of include guards in headers. Comments typically follow conventional C styles, and source files often carry a standard header with copyright notices and version information.

While FreeBSD, NetBSD, and OpenBSD each maintain their own coding guides, they share core BSDstyle principles and periodically publish updates. In practice, teams may adjust rules to accommodate newer language features or toolchains, but the emphasis on portability, explicitness, and readability remains.

Today BSDstyle serves as a historical reference in Unix-like development and continues to influence coding habits in BSD projects and in some open-source communities that trace lineage to BSD origins.