rcsfile(4)                                                       rcsfile(4)




 NAME    [Toc]    [Back]
      rcsfile - format of RCS files

 DESCRIPTION    [Toc]    [Back]
      An RCS file is an ASCII file.  Its contents are described by the
      grammar below.  The text is free format, i.e., spaces, tabs and
      newline characters have no significance except in strings.  Strings
      are enclosed by @ symbols.  If a string contains the @ symbol, the
      symbol must be doubled.

      The meta syntax uses the following conventions:

           |         (bar) Separates alternatives.
           {...}     (braces) Encloses optional phrases.
           {...}*    Encloses phrases that may be repeated zero or more
                     times.
           {...}+    Encloses phrases that must appear at least once and may
                     be repeated.
           <...>     Encloses nonterminals.

    RCS File Grammar    [Toc]    [Back]
      Identifiers are case sensitive.  Keywords are in lowercase only.  The
      sets of keywords and identifiers may overlap.

      <rcstext>   ::= <admin> {<delta>}* <desc> {<deltatext>}*

      <admin>     ::= head    {<num>};
                      access  {<id>}*;
                      symbols {<id> : <num>}*;
                      locks   {<id> : <num>}*; {strict ;}
                      comment {<string>};

      <delta>     ::= <num>
                      date    <num>;
                      author  <id>;
                      state   {<id>};
                      branches {<num>}*;
                      next    {<num>};

      <desc>      ::= desc    <string>

      <deltatext> ::= <num>
                      log     <string>
                      text    <string>

      <num>       ::= {<digit>{.}}+

      <digit>     ::= 0 | 1 | ... | 9

      <id>        ::= <letter>{<idchar>}*




 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003






 rcsfile(4)                                                       rcsfile(4)




      <letter>    ::= A | B | ... | Z | a | b | ... | z

      <idchar>    ::= Any printing ASCII character except space,
                      tab, carriage return, newline, and <special>.

      <special>   ::= ; | : | , | @

      <string>    ::= @{any ASCII character, with "@" doubled}*@

    RCS File Structure    [Toc]    [Back]
      The <delta> nodes form a tree.  All nodes whose numbers consist of a
      single 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).

      All <delta> nodes whose numbers consist of 2n fields (n>=2) (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 2(n-1) 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 numbers.





























 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003






 rcsfile(4)                                                       rcsfile(4)




 EXAMPLES    [Toc]    [Back]
                                   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  /
                                  \     /
                                   \   /
                                    \ /

 WARNINGS    [Toc]    [Back]
      RCS is designed to be used with text (ASCII) files only.  Using RCS
      with nontext (binary) files results in data corruption.

 AUTHOR    [Toc]    [Back]
      rcsfile was developed by Walter F. Tichy, Purdue University, West
      Lafayette, IN 47907.  Revision Number: 3.0.  Release Date: 83/05/11.
      Copyright 1982 by Walter F. Tichy.

 SEE ALSO    [Toc]    [Back]
      ci(1), co(1), ident(1), rcs(1), rcsdiff(1), rcsmerge(1), rlog(1),
      rcsintro(5).


 Hewlett-Packard Company            - 3 -   HP-UX 11i Version 2: August 2003