The sccsfile file is a text file consisting of six logical parts: checksum, delta table, user names, flags, comments, and body.
Note that there are lines throughout an SCCS file that begin with the ASCII SOH (start of heading) character (octal 001). This character is called the control character and is represented graphically as an @ (at sign) in the following text.
The checksum is the first line of an SCCS file. The value of the checksum is the sum of all characters, except those of the first line.
The format of the line is @hDDDDD.
DDDDD is the serial number corresponding to the delta for the control line (a 5-digit string from 00000 to 99999). @h designates a magic number of 064001 octal (or 0x6801).
The delta table provides information about each delta including type, SCCS identification (SID), date and time of creation, and comments.
The delta table consists of a variable number of entries such as the following: Contains the number of lines inserted or deleted or unchanged, respectively. where: type is the type of delta, with D designating a normal delta and R designating a removed delta. SID is the SCCS identification of the delta. yy/mm/dd hh:mm:ss is the date and time the delta was created. If yy is 69 to 99, the year is interpreted as being in the twentieth century, i.e. 19yy. Otherwise, the year is interpreted as being in the twenty-first century, i.e. 20yy. user is the username that corresponds to the real user ID at the time the delta was created. DDDDD is the serial number of the delta and its predecessor, respectively. Contains the serial numbers of the deltas included. This line is optional. Contains the serial numbers of deltas excluded. This line is optional. Contains the serial numbers of the deltas ignored. This line is optional. Contains a modification request (MR) number associated with the delta, one MR number per line. These lines are optional. Contains comment lines associated with the delta. Ends the delta table entry.
The user names section contains user names and numerical group IDs of users who are allowed to add or remove deltas from the SCCS file, separated by newline characters. The bracketing lines @u and @U surround the lines containing the list. An empty list allows any user to make a delta.
The flags section contains definitions of internal keywords.
The comments section contains descriptive information about the file. Typically, this section contains a description of the purpose of the file. Bracketing lines @t and @T surrounding text designate the Comments section.
The body contains the actual text lines, intermixed with control lines. Control lines begin with a control character, text lines do not. There are three kinds of control lines: insert, delete, and end, represented by: @I DDDDD
The digit string is the serial number corresponding to the delta for the control line.
Keywords are used internally in the system. For more information about their use, see the admin(1) reference page. The format of each line is as follows: @f <character> <optional text>
The following keywords are defined: <type of program> <program name> <module name> <floor> <ceiling> <default SID> <lock releases> <user defined>
The characters are used as follows: Allows the use of the -b flag on the get command to cause a branch in the delta tree. Defines the highest release number, less than or equal to 9999, that can be retrieved by a get command for editing. This release number is called the ceiling release number. Defines the default SID to be used when one is not specified with a get command. Defines the lowest release number between 0 and 9999, that can be retrieved by a get command for editing. This release number is called the floor release number. Controls the error warning message No ID keywords. When this character is not present, this message is only a warning. When this character is present, the file is not used and the delta is not made. Causes the get command to allow concurrent edits of the same base SID. Defines a list of releases that cannot be edited with get using the -e flag. Defines the first choice for the replacement text of the [email protected]% identification keyword. Causes the delta command to insert a delta that applies no changes for those skipped releases when a delta for a new release is made. For example, delta 5.1 is made after delta 2.1, skipping releases 3 and 4. When this character is omitted, it causes skipped releases to be completely empty. Defines the replacement for the %Q% identification keyword. Defines the replacement for the %Y% identification keyword. Controls prompting for MR numbers in addition to comments. If optional text is present, it defines an MR number validity checking program.
Commands: admin(1), cdc(1), comb(1), delta(1), get(1), prs(1), rmdel(1), sact(1), sccsdiff(1), sccshelp(1), unget(1), val(1), what(1). delim off