CO(1)CO(1)NAMEco - check out RCS revisions
SYNOPSISco [options] file ...
DESCRIPTIONco retrieves a revision from each RCS file and stores it into the
corresponding working file.
Pathnames 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 may 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 may 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 may 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
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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:
1.15 $ 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: 1.15
$. 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: 1.15 $ 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 1.15 instead of $Revision:
1.15 $. 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
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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 may 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
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-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 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 may 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 may be 3, 4, or 5. This may 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
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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 will lose its default branch.
An RCS revision generated while emulating version 4 or earlier will
have a timestamp that is off by up to 13 hours. A revision
extracted while emulating version 4 or earlier will contain
abbreviated dates of the form yy/mm/dd instead of yyyy/mm/dd and may
also contain different white space 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 may 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.
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$Date$
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 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.
$Id$ 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 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 name of the RCS file without a path.
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$Revision$
The revision number assigned to the revision.
$Source$
The full pathname of the RCS file.
$State$
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.
FILESco 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.
DIAGNOSTICS
The RCS pathname, the working pathname, 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.
Revision Number: 5.7; Release Date: 1998/11/21.
Copyright c 1982, 1988, 1989 by Walter F. Tichy.
Copyright c 1990, 1991, 1992, 1993, 1994, 1995 by Paul Eggert.
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CO(1)CO(1)SEE ALSOci(1), ctime(3), date(1), ident(1), make(1), rcs(1), rcsdiff(1),
rcsintro(1), rcsmerge(1), rlog(1), rcsfile(4), RCSsource(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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