sccs

sccs [options] subcommand [subcommand_options] file ...

-rSID
    Specifies an SCCS ID (SID) for the target version, passed to subcommands like get or delta.

-ccutoff
    Defines a cutoff date and time (e.g., YYMMDDHHMMSS), typically used by get or prs to filter revisions.

-i
    Shorthand for invoking admin -i, used to create a new SCCS file from an existing plain file.

-e
    Shorthand for invoking get -e, used to retrieve a specific version of a file for editing.

-d
    Shorthand for invoking delta, used to commit changes and create a new SCCS delta.

-q
    Suppresses all command output, useful for scripting where only the exit status matters.

-s
    Suppresses the printing of the SCCS Identification String (SID) to standard output.

subcommand
    The specific SCCS utility to execute (e.g., get, delta, admin, prs).

subcommand_options
    Options specific to the chosen SCCS subcommand.

file ...
    One or more source files (or SCCS files prefixed with s.) to operate on.

SCCS (Source Code Control System) is one of the earliest version control systems, originating from Bell Labs in the early 1970s. It was designed to manage changes to source code files and other text documents. The sccs command itself acts as a convenient front-end, simplifying interaction with the underlying SCCS utilities like get, delta, admin, prs, and others. It allows users to retrieve specific versions, make changes, commit new versions, and manage the SCCS file attributes.

Unlike modern systems that often store full copies or diffs, SCCS uses a unique delta-based storage mechanism where it stores the original version and then deltas (changes) for subsequent versions. While largely superseded by systems like RCS, CVS, Subversion, and Git due to its perceived complexity and lack of distributed capabilities, SCCS remains historically significant and can still be found on some legacy Unix systems. It's particularly noted for its robust handling of file revisions and its influence on later version control designs.

SCCS is largely considered obsolete for modern development, having been superseded by more advanced and user-friendly systems. It is a centralized, local-file-based system, lacking network or distributed capabilities. Its command-line interface can be arcane, and it requires specific file naming conventions (e.g., s.filename), presenting a steeper learning curve for users accustomed to modern version control systems.

SCCS files are not plain text files; they are binary files prefixed with s. (e.g., s.main.c). They contain the original file content and a series of deltas, along with metadata, making them directly unreadable and uneditable by standard text editors. Users interact with them exclusively through sccs commands.

SCCS stores changes as deltas. The first version (initial delta) is stored completely, and subsequent versions are stored as instructions to transform one version into another. This differs significantly from many modern version control systems that store full snapshots or use reverse deltas.

SCCS was developed by Marc Rochkind at Bell Labs starting in 1972. It was one of the first widely used version control systems, predating RCS. Its core innovation was the delta-based storage mechanism, which efficiently stored only the changes between versions rather than full copies, making it suitable for disk-space-constrained systems of its era. SCCS influenced the design of subsequent version control systems and became a standard part of many Unix distributions, including System V and BSD. While its direct use diminished with the rise of RCS and later networked VCS like CVS and Subversion, and eventually distributed VCS like Git, its principles of revision tracking and delta storage were foundational to the evolution of software configuration management.

get(1), delta(1), admin(1), prs(1), rmdel(1), unget(1), cdc(1), what(1), rcs(1), git(1)