jammy (1) co.1.gz

Provided by: rcs_5.10.1-1_amd64 bug

NAME

       co - check out RCS revisions

SYNOPSIS

       co [options] file ...

DESCRIPTION

       co retrieves a revision from each RCS file and stores it into the corresponding working file.

       Filenames  matching an RCS suffix denote RCS files; all others denote working files.  Names are paired as
       explained in ci(1).

       Revisions of an RCS file can be checked out locked or unlocked.  Locking a revision prevents  overlapping
       updates.   A  revision  checked  out  for  reading or processing (e.g., compiling) need not be locked.  A
       revision checked out for editing and later checkin must normally be locked.  Checkout with locking  fails
       if  the  revision  to  be  checked  out  is currently locked by another user.  (A lock can be broken with
       rcs(1).)  Checkout with locking also requires the caller to be on the access list of the RCS file, unless
       he  is  the owner of the file or the superuser, or the access list is empty.  Checkout without locking is
       not subject to accesslist restrictions, and is not affected by the presence of locks.

       A revision is selected by options for revision or branch number, checkin  date/time,  author,  or  state.
       When  the  selection  options are applied in combination, co retrieves the latest revision that satisfies
       all of them.  If none of the selection options is specified, co retrieves  the  latest  revision  on  the
       default  branch  (normally  the  trunk, see the -b option of rcs(1)).  A revision or branch number can be
       attached to any of the options -f, -I, -l, -M, -p, -q, -r, or -u.  The options -d (date), -s (state), and
       -w  (author)  retrieve from a single branch, the selected branch, which is either specified by one of -f,
       ..., -u, or the default branch.

       A co command applied to an RCS file with no revisions creates a  zero-length  working  file.   co  always
       performs keyword substitution (see below).

OPTIONS

       -r[rev]
              retrieves  the  latest  revision  whose  number  is less than or equal to rev.  If rev indicates a
              branch rather than a revision, the latest revision  on  that  branch  is  retrieved.   If  rev  is
              omitted, the latest revision on the default branch (see the -b option of rcs(1)) is retrieved.  If
              rev is $, co determines the revision number from keyword values in the working file.  Otherwise, a
              revision  is  composed  of  one  or  more numeric or symbolic fields separated by periods.  If rev
              begins with a period, then the default branch (normally the trunk) is prepended to it.  If rev  is
              a  branch  number  followed  by  a  period,  then the latest revision on that branch is used.  The
              numeric equivalent of a symbolic field is specified with the -n option of the commands  ci(1)  and
              rcs(1).

       -l[rev]
              same as -r, except that it also locks the retrieved revision for the caller.

       -u[rev]
              same  as -r, except that it unlocks the retrieved revision if it was locked by the caller.  If rev
              is omitted, -u retrieves the revision locked by  the  caller,  if  there  is  one;  otherwise,  it
              retrieves the latest revision on the default branch.

       -f[rev]
              forces  the  overwriting  of  the working file; useful in connection with -q.  See also FILE MODES
              below.

       -kkv   Generate keyword strings using the default  form,  e.g.  $Revision:  5.10.1  $  for  the  Revision
              keyword.   A  locker's name is inserted in the value of the Header, Id, and Locker keyword strings
              only as a file is being locked, i.e. by ci -l and co -l.  This is the default.

       -kkvl  Like -kkv, except that a locker's name is always inserted  if  the  given  revision  is  currently
              locked.

       -kk    Generate  only  keyword  names  in  keyword  strings; omit their values.  See KEYWORD SUBSTITUTION
              below.  For example,  for  the  Revision  keyword,  generate  the  string  $Revision$  instead  of
              $Revision: 5.10.1 $.  This option is useful to ignore differences due to keyword substitution when
              comparing different revisions of a file.  Log messages are inserted after $Log$ keywords  even  if
              -kk is specified, since this tends to be more useful when merging changes.

       -ko    Generate  the  old keyword string, present in the working file just before it was checked in.  For
              example, for the Revision keyword, generate the string $Revision:  1.1  $  instead  of  $Revision:
              5.10.1  $ if that is how the string appeared when the file was checked in.  This can be useful for
              file formats that cannot tolerate any changes to substrings  that  happen  to  take  the  form  of
              keyword strings.

       -kb    Generate  a  binary  image  of the old keyword string.  This acts like -ko, except it performs all
              working file input and output in binary mode.  This makes little  difference  on  Posix  and  Unix
              hosts,  but  on  DOS-like hosts one should use rcs -i -kb to initialize an RCS file intended to be
              used for binary files.  Also, on all hosts, rcsmerge(1) normally refuses to merge files  when  -kb
              is in effect.

       -kv    Generate only keyword values for keyword strings.  For example, for the Revision keyword, generate
              the string 5.10.1 instead of $Revision: 5.10.1 $.  This can help  generate  files  in  programming
              languages  where it is hard to strip keyword delimiters like $Revision: $ from a string.  However,
              further keyword substitution cannot be performed once the  keyword  names  are  removed,  so  this
              option should be used with care.  Because of this danger of losing keywords, this option cannot be
              combined with -l, and the owner write permission of the working file is turned off;  to  edit  the
              file later, check it out again without -kv.

       -p[rev]
              prints  the  retrieved revision on the standard output rather than storing it in the working file.
              This option is useful when co is part of a pipe.

       -q[rev]
              quiet mode; diagnostics are not printed.

       -I[rev]
              interactive mode; the user is prompted and  questioned  even  if  the  standard  input  is  not  a
              terminal.

       -ddate retrieves the latest revision on the selected branch whose checkin date/time is less than or equal
              to date.  The date and time can be given in free format.  The time zone LT stands for local  time;
              other  common  time zone names are understood.  For example, the following dates are equivalent if
              local time is January 11, 1990, 8pm  Pacific  Standard  Time,  eight  hours  west  of  Coordinated
              Universal Time (UTC):

                     8:00 pm lt
                     4:00 AM, Jan. 12, 1990           default is UTC
                     1990-01-12 04:00:00+00           ISO 8601 (UTC)
                     1990-01-11 20:00:00-08           ISO 8601 (local time)
                     1990/01/12 04:00:00              traditional RCS format
                     Thu Jan 11 20:00:00 1990 LT      output of ctime(3) + LT
                     Thu Jan 11 20:00:00 PST 1990     output of date(1)
                     Fri Jan 12 04:00:00 GMT 1990
                     Thu, 11 Jan 1990 20:00:00 -0800  Internet RFC 822
                     12-January-1990, 04:00 WET

              Most  fields  in  the  date and time can be defaulted.  The default time zone is normally UTC, but
              this can be overridden by the -z option.  The other defaults are determined  in  the  order  year,
              month,  day,  hour,  minute, and second (most to least significant).  At least one of these fields
              must be provided.  For omitted fields that are of higher significance than  the  highest  provided
              field,  the  time  zone's  current  values  are assumed.  For all other omitted fields, the lowest
              possible values are assumed.  For example, without -z, the date 20, 10:30 defaults to 10:30:00 UTC
              of  the  20th  of  the UTC time zone's current month and year.  The date/time must be quoted if it
              contains spaces.

       -M[rev]
              Set the modification time on the new working file to be the date of the retrieved  revision.   Use
              this option with care; it can confuse make(1).

       -sstate
              retrieves the latest revision on the selected branch whose state is set to state.

       -S     Enable  self-same  mode.   In  this mode, the owner of a lock is unimportant, just that it exists.
              Effectively, this means the user cannot check out the same revision twice.

       -T     Preserve the modification time on the RCS file even if the RCS file  changes  because  a  lock  is
              added or removed.  This option can suppress extensive recompilation caused by a make(1) dependency
              of some other copy of the working file on the RCS  file.   Use  this  option  with  care;  it  can
              suppress recompilation even when it is needed, i.e. when the change of lock would mean a change to
              keyword strings in the other working file.

       -w[login]
              retrieves the latest revision on the selected branch which was checked in by the user  with  login
              name login.  If the argument login is omitted, the caller's login is assumed.

       -jjoinlist
              generates  a  new revision which is the join of the revisions on joinlist.  This option is largely
              obsoleted by rcsmerge(1) but is retained for backwards compatibility.

              The joinlist is a comma-separated list of pairs of the form rev2:rev3, where  rev2  and  rev3  are
              (symbolic  or  numeric)  revision  numbers.   For the initial such pair, rev1 denotes the revision
              selected by the above options -f, ..., -w.   For  all  other  pairs,  rev1  denotes  the  revision
              generated by the previous pair.  (Thus, the output of one join becomes the input to the next.)

              For each pair, co joins revisions rev1 and rev3 with respect to rev2.  This means that all changes
              that transform rev2 into rev1 are applied to a copy of rev3.  This is particularly useful if  rev1
              and  rev3  are the ends of two branches that have rev2 as a common ancestor.  If rev1<rev2<rev3 on
              the same branch, joining generates a new revision which is like rev3, but with  all  changes  that
              lead  from  rev1  to  rev2 undone.  If changes from rev2 to rev1 overlap with changes from rev2 to
              rev3, co reports overlaps as described in merge(1).

              For the initial pair, rev2 can be omitted.  The default is the common ancestor.   If  any  of  the
              arguments  indicate  branches, the latest revisions on those branches are assumed.  The options -l
              and -u lock or unlock rev1.

       -V     Print RCS's version number.

       -Vn    Emulate RCS version n, where n can be 3, 4, or 5.  This can be useful when interchanging RCS files
              with  others  who  are  running  older  versions  of  RCS.   To  see  which  version  of  RCS your
              correspondents are running, have them invoke rcs -V; this works with newer versions of RCS.  If it
              doesn't  work,  have  them  invoke  rlog  on an RCS file; if none of the first few lines of output
              contain the string branch: it is version 3; if the dates'  years  have  just  two  digits,  it  is
              version  4; otherwise, it is version 5.  An RCS file generated while emulating version 3 loses its
              default branch.  An RCS revision generated while emulating version 4 or earlier has a  time  stamp
              that is off by up to 13 hours.  A revision extracted while emulating version 4 or earlier contains
              abbreviated dates of the form yy/mm/dd and  can  also  contain  different  white  space  and  line
              prefixes in the substitution for $Log$.

       -xsuffixes
              Use suffixes to characterize RCS files.  See ci(1) for details.

       -zzone specifies  the date output format in keyword substitution, and specifies the default time zone for
              date in the -ddate option.  The zone should be empty, a numeric UTC offset, or the special  string
              LT  for  local  time.   The default is an empty zone, which uses the traditional RCS format of UTC
              without any time zone indication and with slashes separating the parts  of  the  date;  otherwise,
              times  are  output  in  ISO  8601 format with time zone indication.  For example, if local time is
              January 11, 1990, 8pm Pacific Standard Time, eight hours west of UTC, then the time is  output  as
              follows:

                     option    time output
                     -z        1990/01/12 04:00:00        (default)
                     -zLT      1990-01-11 20:00:00-08
                     -z+05:30  1990-01-12 09:30:00+05:30

              The -z option does not affect dates stored in RCS files, which are always UTC.

KEYWORD SUBSTITUTION

       Strings  of  the  form  $keyword$ and $keyword:...$ embedded in the text are replaced with strings of the
       form $keyword:value$ where keyword and value are pairs listed below.  Keywords can be embedded in literal
       strings or comments to identify a revision.

       Initially,  the  user  enters strings of the form $keyword$.  On checkout, co replaces these strings with
       strings of the form $keyword:value$.  If a revision containing strings of the latter form is checked back
       in,  the  value  fields  will  be  replaced  during  the  next  checkout.   Thus,  the keyword values are
       automatically updated on checkout.  This automatic substitution can be modified by the -k options.

       Keywords and their corresponding values:

       $Author$
              The login name of the user who checked in the revision.

       $Date$ The date and time the revision was checked  in.   With  -zzone  a  numeric  time  zone  offset  is
              appended; otherwise, the date is UTC.

       $Header$
              A  standard  header containing the full RCS file name, the revision number, the date and time, the
              author, the state, and the locker (if locked).  With -zzone a numeric time zone offset is appended
              to the date; otherwise, the date is UTC.

       $Id$   Same as $Header$, except that the RCS file name is without the directory components.

       $Locker$
              The login name of the user who locked the revision (empty if not locked).

       $Log$  The  log  message  supplied during checkin, preceded by a header containing the RCS file name, the
              revision number, the author, and the date and time.  With -zzone a numeric  time  zone  offset  is
              appended;  otherwise,  the date is UTC.  Existing log messages are not replaced.  Instead, the new
              log message is inserted after $Log:...$.  This is useful for accumulating a complete change log in
              a source file.

              Each  inserted  line  is prefixed by the string that prefixes the $Log$ line.  For example, if the
              $Log$ line is “// $Log: tan.cc $”, RCS prefixes each line of the log with “// ”.  This  is  useful
              for languages with comments that go to the end of the line.  The convention for other languages is
              to use a “  ” prefix inside a multiline comment.  For example, the initial log  comment  of  a  C
              program conventionally is of the following form:

                     /∗
                       $Log$
                      ∗/

              For  backwards  compatibility with older versions of RCS, if the log prefix is /∗ or (∗ surrounded
              by optional white space, inserted log lines contain a space instead of / or (; however, this usage
              is obsolescent and should not be relied on.

       $Name$ The  symbolic  name  used  to  check  out  the  revision, if any.  For example, co -rJoe generates
              $Name: Joe $.  Plain co generates just $Name:  $.

       $RCSfile$
              The RCS file name without directory components.

       $Revision$
              The revision number assigned to the revision.

       $Source$
              The full RCS file name.

       $State$
              The state assigned to the revision with the -s option of rcs(1) or ci(1).

       The following characters in keyword values are represented by escape sequences to  keep  keyword  strings
       well-formed.

              char     escape sequence
              tab      \t
              newline  \n
              space    \040
              $        \044
              \        \\

FILE MODES

       The  working  file  inherits  the read and execute permissions from the RCS file.  In addition, the owner
       write permission is turned on, unless -kv is set or the file is checked out unlocked and locking  is  set
       to strict (see rcs(1)).

       If  a  file  with  the  name  of  the working file exists already and has write permission, co aborts the
       checkout, asking beforehand if possible.  If the existing working file is not writable or  -f  is  given,
       the working file is deleted without asking.

FILES

       co  accesses  files  much  as  ci(1) does, except that it does not need to read the working file unless a
       revision number of $ is specified.

ENVIRONMENT

       RCSINIT
              Options prepended to the argument list, separated by spaces.  A backslash escapes spaces within an
              option.   The  RCSINIT  options  are prepended to the argument lists of most RCS commands.  Useful
              RCSINIT options include -q, -V, -x, and -z.

       RCS_MEM_LIMIT
              Normally, for speed, commands either memory map or copy into memory the RCS file if  its  size  is
              less  than  the  memory-limit,  currently  defaulting  to  ``unlimited''.   Otherwise  (or  if the
              initially-tried speedy ways fail), the commands fall back to using standard i/o routines.  You can
              adjust  the  memory limit by setting RCS_MEM_LIMIT to a numeric value lim (measured in kilobytes).
              An empty value is silently ignored.  As a side effect, specifying RCS_MEM_LIMIT inhibits fall-back
              to slower routines.

       TMPDIR Name of the temporary directory.  If not set, the environment variables TMP and TEMP are inspected
              instead and the first value found is taken; if none of them are set, a host-dependent  default  is
              used, typically /tmp.

DIAGNOSTICS

       The RCS file name, the working file name, and the revision number retrieved are written to the diagnostic
       output.  The exit status is zero if and only if all operations were successful.

IDENTIFICATION

       Author: Walter F. Tichy.
       Manual Page Revision: 5.10.1; Release Date: 2022-02-19.
       Copyright © 2010-2022 Thien-Thi Nguyen.
       Copyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.
       Copyright © 1982, 1988, 1989 Walter F. Tichy.

SEE ALSO

       ci(1), ctime(3), date(1), ident(1),  make(1),  rcs(1),  rcsclean(1),  rcsdiff(1),  rcsmerge(1),  rlog(1),
       rcsfile(5).

       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.

LIMITS

       Links to the RCS and working files are not preserved.

       There  is  no  way to selectively suppress the expansion of keywords, except by writing them differently.
       In nroff and troff, this is done by embedding the null-character \& into the keyword.