MirOS Manual: co(1)


CO(1)               UNIX Programmer's Manual                CO(1)

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.

     Pathnames matching an RCS suffix denote RCS files; all oth-
     ers 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., com-
     piling) 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 selec-
     tion 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 key-
     word 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

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          number from keyword values in the working file. Other-
          wise, 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 revi-
          sion if it was locked by the caller.  If rev is omit-
          ted, -u retrieves the revision locked by the caller, if
          there is one; otherwise, it retrieves the latest revi-
          sion 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: 5.13 $ 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 exam-
          ple, for the Revision keyword, generate the string
          $Revision$ instead of $Revision: 5.13 $. This option is
          useful to ignore differences due to keyword substitu-
          tion 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: 5.13 $ 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

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          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
          5.13 instead of $Revision: 5.13 $. This can help gen-
          erate 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):

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               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 pro-
          vided field, the time zone's current values are
          assumed. For all other omitted fields, the lowest pos-
          sible 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.

     -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 recompila-
          tion 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 revi-
          sions on joinlist. This option is largely obsoleted by

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          rcsmerge(1) but is retained for backwards compatibil-
          ity.

          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 ances-
          tor.  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 indi-
          cate 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 con-
          tain 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.

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     -zzone
          specifies the date output format in keyword substitu-
          tion, 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 tradi-
          tional RCS format of UTC without any time zone indica-
          tion 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 com-
     ments 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 sub-
     stitution 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; other-
          wise, the date is UTC.

     $Header$
          A standard header containing the full pathname of the
          RCS file, 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.

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     $Id$ Same as $Header$, except that the RCS filename is
          without a path.

     $Locker$
          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 filename, 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 pre-
          fixes the $Log$ line.  For example, if the $Log$ line
          is " .}S 3 1 "" " "// $Log:" "tan.cc $"" "" ","" "" RCS
          prefixes each line of the log with " .}S 3 1 "" "
          "// "" "" "."" "" "" This is useful for languages with
          comments that go to the end of the line. The convention
          for other languages is to use a " .}S 3 1 "" " "*" " "
          """ "" "" prefix inside a multiline comment. For exam-
          ple, the initial log comment of a C program convention-
          ally 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 name of the RCS file without a path.

     $Revision$
          The revision number assigned to the revision.

     $Source$
          The full pathname of the RCS file.

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

     $LocalID$
          Where LocalID is the value of the environment variable
          RCSLOCALID: The same as $Id$, just under a different
          (user-defined) name.

          If RCSLOCALID begins with an exclamation sign ('!'),
          only this keyword is matched. This is a MirBSD exten-
          sion to the RCSLOCALID handling, which is an OpenBSD
          extension to GNU RCS.

     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. See ci(1) for details.

     RCSLOCALID
          Local keyword to substitute. See above for details.

DIAGNOSTICS

     The RCS pathname, the working pathname, and the revision
     number retrieved are written to the diagnostic output. The

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     exit status is zero if and only if all operations were suc-
     cessful.

IDENTIFICATION

     Author: Walter F. Tichy.
     Manual Page Revision: 5.13; Release Date: 1995/06/01.
     Copyright (C) 1982, 1988, 1989 Walter F. Tichy.
     Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Paul
     Eggert.

SEE ALSO

     rcsintro(1), 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.

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.

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