co(1)co(1)NAMEco - check out RCS revisions
SYNOPSISco [options] file...
OPTIONS
retrieves the latest revision whose number is less than or equal to
rev. If rev indicates a branch rather than a revision, the latest revi‐
sion on that branch is retrieved. If rev is omitted, the latest revi‐
sion 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 equiva‐
lent of a symbolic field is specified with the -n option of the com‐
mands ci(1) and rcs(1). same as -r, except that it also locks the
retrieved revision for the caller. same as -r, except that it unlocks
the retrieved revision 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 revision on the default branch.
forces the overwriting of the working file; useful in connection with
-q. See also FILE MODES below. Generate keyword strings using the
default form, e.g. $Revision: 1.1.6.2 $ 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. Like -kkv, except that a locker's name is
always inserted if the given revision is currently locked. 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 $Revision: 1.1.6.2$. This option is useful
to ignore differences due to keyword substitution when comparing dif‐
ferent revisions of a file. 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: 1.1.6.2 $ 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 key‐
word strings. Generate only keyword values for keyword strings. For
example, for the Revision keyword, generate the string 1.1.6.2 instead
of $Revision: 1.1.6.2 $. 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 per‐
formed 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 work‐
ing file is turned off; to edit the file later, check it out again
without -kv. 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. quiet mode; diagnostics are not printed. inter‐
active mode; the user is prompted and questioned even if the standard
input is not a terminal. 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 note: default is
UTC 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 UTC. The other defaults are determined in the order
year, month, day, hour, minute, and second (most to least sig‐
nificant). 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
UTC of the 20th of the UTC time zone's current month and year.
The date/time must be quoted if it contains spaces. 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). retrieves the latest revision on the selected branch
whose state is set to state. 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. 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 over‐
laps 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. 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 ver‐
sion 4 or earlier will have a timestamp that is off by up to 13
hours. A revision extracted while emulating version 4 or ear‐
lier 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 $Log$. Use suffixes to characterize RCS files.
See ci(1) for details.
DESCRIPTIONco retrieves a revision from each RCS file and stores it into the cor‐
responding 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. Lock‐
ing 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).
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: The login name of the user who
checked in the revision. The date and time (UTC) the revision was
checked in. A standard header containing the full pathname of the RCS
file, the revision number, the date (UTC), the author, the state, and
the locker (if locked). Same as $Header$, except that the RCS filename
is without a path. The login name of the user who locked the revision
(empty if not locked). The log message supplied during checkin, pre‐
ceded by a header containing the RCS filename, the revision number, the
author, and the date (UTC). Existing log messages are not replaced.
Instead, the new log message is inserted after $Log:...$. This is use‐
ful for accumulating a complete change log in a source file. The name
of the RCS file without a path. The revision number assigned to the
revision. The full pathname of the RCS file. The state assigned to
the revision with the -s option of rcs(1) or ci(1).
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 possi‐
ble. If the existing working file is not writable or -f is given, the
working file is deleted without asking.
RESTRICTIONS
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.
The -d option sometimes gets confused, and accepts no date before 1970.
FILESco accesses files much as ci(1) does, except that it does not need to
read the working file.
ENVIRONMENT
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: 1.1.6.2; Release Date: 1993/10/07.
Copyright (C) 1982, 1988, 1989 by Walter F. Tichy.
Copyright (C) 1990, 1991 by Paul Eggert.
SEE ALSOci(1), ctime(3), date(1), ident(1), make(1), rcs(1), rcsdiff(1), rcsin‐
tro(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.
co(1)