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rcsfile(5) rcsfile(5) NAME rcsfile - format of RCS file DESCRIPTION An RCS file's contents are described by the grammar below. The text is free format: space, backspace, tab, newline, vertical tab, form feed, and carriage return (collectively, white space) have no sig- nificance except in strings. However, an RCS file must end in a newline character. Strings are enclosed by @. If a string contains a @, it must be dou- bled; otherwise, strings may contain arbitrary binary data. The meta syntax uses the following conventions: `|' (bar) separates al- ternatives; `{' and `}' enclose optional phrases; `{' and `}*' enclose phrases that may be repeated zero or more times; `{' and `}+' enclose phrases that must appear at least once and may be repeated; Terminal symbols are in boldface; nonterminal symbols are in italics. rcstext ::= admin {delta}* desc {deltatext}* admin ::= head {num}; { branch {num}; } access {id}*; symbols {id : num}*; locks {id : num}*; {strict ;} { comment {string}; } { expand {string}; } { newphrase }* delta ::= num date author state branches next { newphrase }* desc ::= desc deltatext ::= num log { newphrase }* text num ::= {digit{.}}+ digit ::= 0 | 1 | ... | 9 id ::= letter{idchar}* letter ::= any letter idchar ::= any visible graphic character except special special ::= $ | , | . | : | ; | @ string ::= @{any character, with @ doubled}*@ newphrase ::= id word* ; word ::= id | num | string | : Identifiers are case sensitive. Keywords are in lower case only. The sets of keywords and identifiers may overlap. In most environments RCS uses the ISO 8859/1 encoding: letters are octal codes 101-132, 141-172, 300-326, 330-366 and 370-377, visible graphic characters are codes 041-176 and 240-377, and white space characters are codes 010-015 and 040. The newphrase productions in the grammar are reserved for future exten- sions to the format of RCS files. No newphrase will begin with any key- word already in use. The delta nodes form a tree. All nodes whose numbers consist of a sin- gle pair (e.g., 2.3, 2.1, 1.3, etc.) are on the trunk, and are linked through the next field in order of decreasing numbers. The head field in the admin node points to the head of that sequence (i.e., contains the highest pair). The branch node in the admin node indicates the de- fault branch (or revision) for most RCS operations. If empty, the de- fault branch is the highest branch on the trunk. All delta nodes whose numbers consist of 2n fields (n) (e.g., 3.1.1.1, 2.1.2.2, etc.) are linked as follows. All nodes whose first 2n-1 number fields are identical are linked through the next field in order of increasing numbers. For each such sequence, the delta node whose number is identical to the first 2n-2 number fields of the deltas on that sequence is called the branchpoint. The branches field of a node contains a list of the numbers of the first nodes of all sequences for which it is a branchpoint. This list is ordered in increasing num- bers. Example: Head | | / \ v / \ / \ / \ --------- / \ / \ / \ / \ | | / \ / \ / \ / \ | 2.1 | / \ / \ /1.2.1.3\ /1.3.1.1\ | | /1.2.2.2\ /1.2.2.1.1.1\ --------- --------- --------- --------- ------------- ^ ^ | ^ ^ | | | | | | | v | | / \ | --------- / \ | / \ | \ 1.3 / / \ | / \ ---------\ / / \----------- /1.2.1.1\ \ / /1.2.2.1\ --------- \ / --------- ^ | ^ | | | | v | | --------- | | \ 1.2 / | ----------------------\ /--------- \ / \ / | | v --------- \ 1.1 / \ / \ / \ / Fig. 1: A revision tree IDENTIFICATION Author: Walter F. Tichy, Purdue University, West Lafayette, IN, 47907. Revision Number: 1.1.6.4; Release Date: 1994/01/24. Copyright 1982, 1988, 1989 by Walter F. Tichy. Copyright 1990, 1991 by Paul Eggert. SEE ALSO ci(1), co(1), ident(1), rcs(1), rcsdiff(1), rcsmerge(1), rlog(1) Walter F. Tichy, RCS--A System for Version Control, Software--Practice & Experience 15, 7 (July 1985), 637-654. rcsfile(5)