Retrieve the latest revision on the selected branch whose
check-in date and 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, 8 P.M. Pacific Standard Time, eight hours
west of Universal Time Coordinate (UTC):
8:00 P.M. lt
4:00 A.M. Jan. 12, 1990
Note: The default is UTC
1990/01/12 04:00:00
Revision Control System (RCS) date format
Thu Jan 11 20:00:00 1990 LT
output of ctime() +LT
Thu Jan 11 20:00:00 PST 1990
output of date
Fri Jan 12 04:00:00 GMT 1990
Thu, 11 Jan 1990 20:00:00 -0800
Fri-JST, 1990, 1 P.M. Jan 12
12-January-1990, 04:00-WET
Most fields in the date and time can be defaulted. The default
time zone is UTC. The other defaults are determined in 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 UTC of the 20th of the
UTC time zone's current month and year. The date and time must be
quoted if it contains spaces.
-f[rev]
Force the overwriting of the working file; useful in connection
with -q. (See FILE MODES.)
-I[rev]
Set interactive mode; the user is prompted and questioned even
if the standard input is not a terminal.
-jjoinlist
Generate a new revision, which is the join of the revisions on
joinlist. This option is is almost obsolete because of
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 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(1) 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 is 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(1) 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.
-kk
Generate only keyword names in keyword strings; omit their
values. (See KEYWORD SUBSTITUTION.) For example, for the
Revision keyword, generate the string $Revision$
instead of $Revision: 1.11 $. This option is useful to
ignore differences due to keyword substitution when comparing
different revisions of a file.
-kkv
Generate keyword strings using the default form, such as
$Revision: 1.11 $ 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, that is, 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.
-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: 1.11 $ 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 1.11
instead of $Revision: 1.11 $. 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.
-l[rev]
Same as -r, except that it also locks the retrieved
revision for the caller.
-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).
-p[rev]
Print the retrieved revision on the standard output rather than
storing it in the working file. This option is useful when
co(1) is part of a pipe.
-q[rev]
Quiet mode; diagnostics are not printed.
-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(1) 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).
-sstate
Retrieve the latest revision on the selected branch whose state
is set to state.
-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.
-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 $Log$.
-w[logname]
Retrieve the latest revision on the selected branch that was
checked in by the user with login name logname. If the
argument login is omitted, the caller's login is
assumed.
-xsuffixes
Use suffixes to characterize RCS files. See ci(1) for
details.
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 (such as compiling) need not be
locked. A revision checked out for editing and later check in must
usually 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 the caller
is the owner of the file or the superuser, or the access list is
empty. Checkout without locking is not subject to access list
restrictions and is not affected by the presence of locks.
A revision is selected by options for revision or branch number,
check-in date and time, author, or state. When the selection
options are applied in combination, co(1) retrieves the
latest revision that satisfies all of them. If none of the
selection options is specified, co(1) retrieves the latest
revision on the default branch (usually the trunk; see the
-b option of rcs(1)).
A revision or branch number can be attached to any of the following
options: -f -I -l -M -p -q -r -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(1) command applied to an RCS file with no revisions
creates a zero-length working file. co(1) always performs
keyword substitution (see below).
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(1) 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.
Following are keywords and their corresponding values:
$Author$
The login name of the user who checked in the revision.
$Date$
The date and time (UTC) the revision was checked in.
$Header$
A standard header containing the full path name of the RCS
file, the revision number, the date (UTC), 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 check in, preceded 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 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 path name of the RCS file.
$State$
The state assigned to the revision with the -s option of
rcs(1) or ci(1).
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(1) aborts the checkout, asking
first if possible. If the existing working file is not writable or
-f is given, the working file is deleted without asking.
The RCS path name, the working path name, and the revision number
that are retrieved are written to the diagnostic output. The exit
status is zero only if all operations were successful.
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.
Because file-allocation table (FAT) file systems do not provide
POSIX file-system semantics, the co(1) command behaves
differently. In particular, the existing working file without write
permission is not deleted and the new working file is stored with
the temporary file name (beginning with an underscore).