{
    "mode": "man",
    "parameter": "RCSFILE",
    "section": "5",
    "url": "https://www.chedong.com/phpMan.php/man/RCSFILE/5/json",
    "generated": "2026-11-08T00:35:19Z",
    "sections": {
        "NAME": {
            "content": "rcsfile - RCS file format\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "An RCS file's contents are described by the grammar below.\n\nThe  text  is  free format: space, backspace, tab, newline, vertical tab, form feed, and car‐\nriage return (collectively, white space) have no significance except  in  strings.   However,\nwhite space cannot appear within an id, num, or sym, and an RCS file must end with a newline.\n\nStrings  are enclosed by @.  If a string contains a @, it must be doubled; otherwise, strings\ncan contain arbitrary binary data.\n\nThe meta syntax uses the following conventions: `|' (bar) separates alternatives; `{' and `}'\nenclose optional phrases; `{' and `}*' enclose phrases that can  be  repeated  zero  or  more\ntimes;  `{' and '}+' enclose phrases that must appear at least once and can be repeated; Ter‐\nminal symbols are in boldface; nonterminal symbols are in italics.\n\nrcstext   ::=  admin {delta}* desc {deltatext}*\n\nadmin     ::=  head       {num};\n{ branch   {num}; }\naccess     {id}*;\nsymbols    {sym : num}*;\nlocks      {id : num}*;  {strict  ;}\n{ integrity{intstring}; }\n{ comment  {string}; }\n{ expand   {string}; }\n\ndelta     ::=  num\ndate       num;\nauthor     id;\nstate      {id};\nbranches   {num}*;\nnext       {num};\n{ commitid sym; }\n\ndesc      ::=  desc       string\n\ndeltatext ::=  num\nlog        string\ntext       string\n\nnum       ::=  {digit | .}+\n\ndigit     ::=  0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9\n\nid        ::=  {idchar | .}+\n\nsym       ::=  {idchar}+\n\nidchar    ::=  any visible graphic character except special\n\nspecial   ::=  $ | , | . | : | ; | @\n\nstring    ::=  @{any character, with @ doubled}*@\n\nword      ::=  id | num | string | :\n\nintchar   ::=  any character, except @\n\nthirdp    ::=  ^L {intchar}*\n\nintstring ::=  @ {intchar}* {thirdp}* @\n\nIn releases prior to 5.8 (2011-08-30), the grammar included the newphrase production and used\nit in the admin, delta and deltatext productions.  This allowed third-party programs  to  in‐\nteroperate  with  RCS by storing opaque (to RCS) data in the file.  As of 5.8, in the name of\nprogress (towards more systematic file integrity support), the only area reserved for  third-\nparty  interop  is in the (string) value of the integrity field, specifically after the first",
            "subsections": [
                {
                    "name": "^L (formfeed)",
                    "content": "contain @.\n\nIdentifiers are case sensitive.  Keywords are in lower case only.  The sets of  keywords  and\nidentifiers  can  overlap.   In  most  environments RCS uses the ISO 8859/1 encoding: visible\ngraphic characters are codes 041-176 and  240-377,  and  white  space  characters  are  codes\n010-015 and 040.\n\nDates,  which appear after the date keyword, are of the form Y.mm.dd.hh.mm.ss, where Y is the\nyear, mm the month (01-12), dd the day (01-31), hh the hour (00-23), mm the  minute  (00-59),\nand  ss  the  second (00-60).  Y contains just the last two digits of the year for years from\n1900 through 1999, and all the digits of years thereafter.  Dates use the Gregorian calendar;\ntimes use UTC.\n\nThe delta nodes form a tree.  All nodes whose numbers consist of a single  pair  (e.g.,  2.3,\n2.1, 1.3, etc.)  are on the trunk, and are linked through the next field in order of decreas‐\ning  numbers.   The  head  field in the admin node points to the head of that sequence (i.e.,\ncontains the highest pair).  The branch node in the admin node indicates the  default  branch\n(or revision) for most RCS operations.  If empty, the default branch is the highest branch on\nthe trunk.\n\nAll  delta nodes whose numbers consist of 2n fields (n≥2) (e.g., 3.1.1.1, 2.1.2.2, etc.)  are\nlinked as follows.  All nodes whose first 2n-1 number fields are identical are linked through\nthe next field in order of increasing numbers.  For each such sequence, the delta node  whose\nnumber  is identical to the first 2n-2 number fields of the deltas on that sequence is called\nthe branchpoint.  The branches field of a node contains a list of the numbers  of  the  first\nnodes  of  all  sequences  for which it is a branchpoint.  This list is ordered in increasing\nnumbers.\n\nThe following diagram shows an example of an RCS file's organization.\n\n\\h'\\n[lss]u'Head\n\\h'\\n[lss]u'|\n\\h'\\n[lss]u'|\n\\h'\\n[lss]u'v                        / \\\n\\h'\\n[lss]u'---------                   /   \\\n\\h'\\n[lss]u'/ \\          / \\      |       |      / \\         /     \\\n\\h'\\n[lss]u'/   \\        /   \\     |  2.1  |     /   \\       /       \\\n\\h'\\n[lss]u'/     \\      /     \\    |       |    /     \\     /         \\\n/1.2.1.3\\    /1.3.1.1\\   |       |   /1.2.2.2\\   /1.2.2.1.1.1\\\n---------    ---------   ---------   ---------   -------------\n\\h'\\n[lss]u'^            ^           |           ^             ^\n\\h'\\n[lss]u'|            |           |           |             |\n\\h'\\n[lss]u'|            |           v           |             |\n\\h'\\n[lss]u'/ \\           |       ---------      / \\            |\n\\h'\\n[lss]u'/   \\          |       \\  1.3  /     /   \\           |\n\\h'\\n[lss]u'/     \\         ---------\\     /     /     \\-----------\n/1.2.1.1\\      1.3.1       \\   /     /1.2.2.1\\     1.2.2.1.1\n---------                   \\ /      ---------\n\\h'\\n[lss]u'^                        |           ^\n\\h'\\n[lss]u'|                        |           |\n\\h'\\n[lss]u'|                        v           |\n\\h'\\n[lss]u'|                    ---------       |\n\\h'\\n[lss]u'|                    \\  1.2  /       |\n\\h'\\n[lss]u'----------------------\\     /---------\n\\h'\\n[lss]u'1.2.1                    \\   /       1.2.2\n\\h'\\n[lss]u'\\ /\n\\h'\\n[lss]u'|\n\\h'\\n[lss]u'|\n\\h'\\n[lss]u'v\n\\h'\\n[lss]u'---------\n\\h'\\n[lss]u'\\  1.1  /\n\\h'\\n[lss]u'\\     /\n\\h'\\n[lss]u'\\   /\n\\h'\\n[lss]u'\\ /\n\n"
                }
            ]
        },
        "IDENTIFICATION": {
            "content": "Author: Walter F. Tichy.\nManual Page Revision: 5.10.1; Release Date: 2022-02-19.\nCopyright © 2010-2022 Thien-Thi Nguyen.\nCopyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.\nCopyright © 1982, 1988, 1989 Walter F. Tichy.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "ci(1), co(1), ident(1), rcs(1), rcsclean(1), rcsdiff(1), rcsmerge(1), rlog(1).\n\nWalter F. Tichy, RCS--A System for Version Control, Software--Practice  &  Experience  15,  7\n(July 1985), 637-654.\n\nThe  full  documentation  for  RCS is maintained as a Texinfo manual.  If the info(1) and RCS\nprograms are properly installed at your site, the command\n\ninfo rcs\n\nshould give you access to the complete manual.  Additionally, the RCS homepage:\n\nhttp://www.gnu.org/software/rcs/\n\nhas news and links to the latest release, development site, etc.\n\nGNU RCS 5.10.1                               2022-02-19                                   RCSFILE(5)",
            "subsections": []
        }
    },
    "summary": "rcsfile - RCS file format",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "ci",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/ci/1/json"
        },
        {
            "name": "co",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/co/1/json"
        },
        {
            "name": "ident",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/ident/1/json"
        },
        {
            "name": "rcs",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/rcs/1/json"
        },
        {
            "name": "rcsclean",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/rcsclean/1/json"
        },
        {
            "name": "rcsdiff",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/rcsdiff/1/json"
        },
        {
            "name": "rcsmerge",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/rcsmerge/1/json"
        },
        {
            "name": "rlog",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/rlog/1/json"
        },
        {
            "name": "info",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/info/1/json"
        }
    ]
}