### 5.1 Overview

An SCCS file contains two parts, the header and the body. The header contains information about both the file as a whole and also information about each version stored in the file. After this comes the body itself, which is a stream of fragments from the controlled file interspersed with control information which indicates which versions these fragments appear in.

Most of the control information for SCCS files appears on lines which are marked as special by the character whose value is 1 (ASCII SOH); this is usually referred to as ‘`^A`’. Lines in SCCS files always end with a line feed (ASCII LF) rather than a carriage return (ASCII CR) followed by a line feed.