bionic (5) rcsfile.5.gz

Provided by: rcs_5.9.4-4_amd64 bug

NAME

       rcsfile - RCS file format

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 significance except in strings.  However, white space  cannot  appear
       within an id, num, or sym, and an RCS file must end with a newline.

       Strings  are enclosed by @.  If a string contains a @, it must be doubled; otherwise, strings can contain
       arbitrary binary data.

       The meta syntax uses the following conventions: `|' (bar) separates alternatives;  `{'  and  `}'  enclose
       optional  phrases;  `{'  and  `}*'  enclose phrases that can be repeated zero or more times; `{' and '}+'
       enclose phrases that must appear at least once and can 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    {sym : num}*;
                      locks      {id : num}*;  {strict  ;}
                      { integrity{intstring}; }
                      { comment  {string}; }
                      { expand   {string}; }

       delta     ::=  num
                      date       num;
                      author     id;
                      state      {id};
                      branches   {num}*;
                      next       {num};
                      { commitid sym; }

       desc      ::=  desc       string

       deltatext ::=  num
                      log        string
                      text       string

       num       ::=  {digit | .}+

       digit     ::=  0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

       id        ::=  {idchar | .}+

       sym       ::=  {idchar}+

       idchar    ::=  any visible graphic character except special

       special   ::=  $ | , | . | : | ; | @

       string    ::=  @{any character, with @ doubled}*@

       word      ::=  id | num | string | :

       intchar   ::=  any character, except @

       thirdp    ::=  ^L {intchar}*

       intstring ::=  @ {intchar}* {thirdp}* @

       In  releases  prior to 5.8 (2011-08-30), the grammar included the newphrase production and used it in the
       admin, delta and deltatext productions.  This allowed third-party programs to interoperate  with  RCS  by
       storing  opaque  (to  RCS) data in the file.  As of 5.8, in the name of progress (towards more systematic
       file integrity support), the only area reserved for third-party interop is in the (string) value  of  the
       integrity field, specifically after the first ^L (formfeed).  A further restriction (for all programs) is
       that the integrity value must not contain @.

       Identifiers are case sensitive.  Keywords are in lower case only.  The sets of keywords  and  identifiers
       can overlap.  In most environments RCS uses the ISO 8859/1 encoding: visible graphic characters are codes
       041-176 and 240-377, and white space characters are codes 010-015 and 040.

       Dates, which appear after the date keyword, are of the form Y.mm.dd.hh.mm.ss, where Y is the year, mm the
       month (01-12), dd the day (01-31), hh the hour (00-23), mm the minute (00-59), and ss the second (00-60).
       Y contains just the last two digits of the year for years from 1900 through 1999, and all the  digits  of
       years thereafter.  Dates use the Gregorian calendar; times use UTC.

       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).  The
       branch node in the admin node indicates the default branch (or revision) for  most  RCS  operations.   If
       empty, the default branch is the highest branch on the trunk.

       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 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 numbers.

       The following diagram shows an example of an RCS file's organization.

                                  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\      1.3.1       \   /     /1.2.2.1\     1.2.2.1.1
       ---------                   \ /      ---------
           ^                        |           ^
           |                        |           |
           |                        v           |
           |                    ---------       |
           |                    \  1.2  /       |
           ----------------------\     /---------
         1.2.1                    \   /       1.2.2
                                   \ /
                                    |
                                    |
                                    v
                                ---------
                                \  1.1  /
                                 \     /
                                  \   /
                                   \ /

IDENTIFICATION

       Author: Walter F. Tichy.
       Manual Page Revision: 5.9.4; Release Date: 2018-01-01.
       Copyright © 2010-2015 Thien-Thi Nguyen.
       Copyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.
       Copyright © 1982, 1988, 1989 Walter F. Tichy.

SEE ALSO

       ci(1), co(1), ident(1), rcs(1), rcsclean(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.

       The  full  documentation  for RCS is maintained as a Texinfo manual.  If the info(1) and RCS programs are
       properly installed at your site, the command

              info rcs

       should give you access to the complete manual.  Additionally, the RCS homepage:

              http://www.gnu.org/software/rcs/

       has news and links to the latest release, development site, etc.