co(1) DG/UX R4.11MU05 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 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, the access list is empty or unless
caller is the [file/object] owner or is able to override any access
controls. On a traditional DG/UX system, you must have an effective
UID of 0 (root) to override access controls. On a system with with
DG/UX information security, one or more specific capabilities must be
enabled in your effective capability set. 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. 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: 1997/10/18 $ 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: 1997/10/18 $. This option is useful to ignore
differences due to keyword substitution when comparing
different revisions of a file.
-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: 1997/10/18 $ if that is how the string appeared
when the file was checked in. This can be useful for binary
file formats that cannot tolerate any changes to substrings
that happen to take the form of keyword strings.
-kv Generate only keyword values for keyword strings. For
example, for the Revision keyword, generate the string
1997/10/18 instead of $Revision: 1997/10/18 $. 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 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 (GMT):
8:00 pm lt
4:00 AM, Jan. 12, 1990 note: default is GMT
1990/01/12 04:00:00 RCS date 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
Fri-JST, 1990, 1pm Jan 12
12-January-1990, 04:00-WET
Most fields in the date and time may be defaulted. The
default time zone is GMT. 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, the date 20, 10:30
defaults to 10:30:00 GMT of the 20th of the GMT 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.
-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.
-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 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 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.
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.
$Date$ The date and time (GMT) the revision was checked in.
$Header$
A standard header containing the full pathname of the RCS
file, the revision number, the date (GMT), the author, the
state, and the locker (if locked).
$Id$ Same as $Header$, except that the RCS file name 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 (GMT). 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.
$RCSfile$
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.
$State$
The state assigned to the revision with the -s option of
rcs(1) or ci(1).
$What$ The $RCSfile$ and $Revision$ keywords expanded and preceded by
the string @(#). This is recognized by the what(1) command.
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.
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: 1997/10/18; Release Date: 08:32:45.
Copyright © 1982, 1988, 1989 by Walter F. Tichy.
Copyright © 1990, 1991 by Paul Eggert.
SEE ALSO
ci(1), ctime(3C), date(1), ident(1), make(1), rcs(1), rcsdiff(1),
rcsintro(1), rcsmerge(1), rlog(1), rcsfile(4)
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.
BUGS
The -d option sometimes gets confused, and accepts no date before
1970.
Licensed material--property of copyright holder(s)