co Commands

FUNCTION
Check out RCS Source;

SYNOPSIS
co [ options ] file ...

DESCRIPTION
Co retrieves a revision from each RCS file and stores it into the
corresponding working file. Each file name ending in ,v is taken to
be an RCS file; all other files are assumed to be working files. If
only a working file is given, co tries to find the corresponding file
in the RCS directory and then in the current directory. For more
details, see the file naming section below.

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. Co with locking fails if the revision to be checked out is
currently locked by another user. (A lock may be broken with the rcs
command.) Co 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. Co 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). A revision or branch
number may be attached to any of the options -f, -l, -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).

-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) is retrieved. rev is composed of one or more
numeric or symbolic fields separated by .. The numeric
equivalent of a symbolic field is specified with the -n option of
the commands ci and rcs.

-l[rev] same as -r, except that it also locks the retrieved revision for
the caller. See option -r for handling of the revision number
rev.

-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
latest revision locked by the caller; if no such lock exists, 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 the section on file modes below.

-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.

-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 and are converted to local time.
Examples of formats for date:

22-April-1982
17:20-CDT
2:25 AM
Dec. 29, 1983
Tue-PDT, 1981
4pm Jul 21 (free format)
Fri, April 16 15:52:25 EST 1982 (output of ctime).

Most fields in the date and time may be defaulted. co determines
the defaults 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 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 of the 20th of the current month and current year.
The date/time must be quoted if it contains spaces.

-sstate retrieves the latest revision on the selected branch whose state
is set to state.

[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.

joinlist
generates a new revision which is the join of the revisions on
joinlist. 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 -r, ..., -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 prints a
warning and includes the overlapping sections, delimited by the
lines

<<<<<<<
rev1
=======
rev3
>>>>>>>

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.

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.

Keyword : Value
===========+=========================================================
$Author: dice $ : The login name of the user who checked in the revision.
-----------+---------------------------------------------------------
$Date: 1994/08/18 05:39:56 $ : The date and time the revision was checked in.
-----------+---------------------------------------------------------
$Header: /home/dice/com/master/Doc/RCS/dice_commands.doc,v 30.8 1994/08/18
05:39:56 dice Exp dice $ : A standard header containing the full pathname
: of the RCS file, the revision number, the date, the author,
: the state, and the locker (if locked).
-----------+---------------------------------------------------------
$Id: dice_commands.doc,v 30.8 1994/08/18 05:39:56 dice Exp dice $
: Same as $Header: /home/dice/com/master/Doc/RCS/dice_commands.doc,
:v 30.8 1994/08/18 05:39:56 dice Exp dice $, except more useful.
:Rather than the full path name as, this leaves just the file name.
-----------+---------------------------------------------------------
$Locker: dice $ : The login name of the user who locked the revision
: (empty if not locked).
-----------+---------------------------------------------------------
$Log: dice_commands.doc,v $
# Revision 30.8 1994/08/18 05:39:56 dice
# .
#
# Revision 30.0 1994/06/10 17:57:04 dice
# .
#
# Revision 30.0 1994/06/10 17:57:04 dice
# .
# : The log message supplied during checkin, preceded by a
: header containing the RCS file name, the revision
: number, the author, and the date. Existing log
: messages are NOT replaced. Instead, the new log
: message is inserted after $Log: dice_commands.doc,v $
# Revision 30.8 1994/08/18 05:39:56 dice
# .
#
# Revision 30.0 1994/06/10 17:57:04 dice
# .
#
# Revision 30.0 1994/06/10 17:57:04 dice
# .
#. This is useful for
: accumulating a complete change log in a source file.
-----------+---------------------------------------------------------
$RCSfile: dice_commands.doc,v $ : The name of the RCS file without path.
-----------+---------------------------------------------------------
$Revision: 30.8 $ : The revision number assigned to the revision.
-----------+---------------------------------------------------------
$Source: /home/dice/com/master/Doc/RCS/dice_commands.doc,v $ : The full pathname of the RCS file.
-----------+---------------------------------------------------------
$State: Exp $ : State of the revision as set by the -s option of rcs or
: ci.
-----------+---------------------------------------------------------

FILE NAMING
Pairs of RCS files and working files may be specified in 3 ways (see
also the example section).

1) Both the RCS file and the working file are given. The RCS file
name is of the form path1/workfile,v and the working file name is
of the form path2/workfile, where path1/ and path2/ are (possibly
different or empty) paths and workfile is a file name.

2) Only the RCS file is given. Then the working file is created in
the current directory and its name is derived from the name of the
RCS file by removing path1/ and the suffix ,v.

3) Only the working file is given. Then co looks for an RCS file of
the form path2/RCS/workfile,v or path2/workfile,v (in this order).

If the RCS file is specified without a path in 1) and 2), then co
looks for the RCS file first in the directory RCS, then in the
directory contained in the file RCS_LINK, followed by the current
directory.

EXAMPLES
Suppose the current directory contains a subdirectory RCS with an RCS
file io.c,v. Then all of the following commands retrieve the latest
revision from RCS/io.c,v and store it into io.c.

co io.c
co RCS/io.c,v
co io.c,v
co io.c RCS/io.c,v
co io.c io.c,v
co RCS/io.c,v io.c
co io.c,v io.c

FILE MODES
If a file with the name of the working file exists already and has
write permission, co aborts the checkout if -q is given, or asks
whether to abort if -q is not given. If the existing working file is
not writable or -f is given, the working file is deleted without
asking.

DIAGNOSTICS
The RCS file name, the working file name, and the revision number
retrieved are written to the diagnostic output. The exit status
always refers to the last file checked out, and is 0 if the operation
was successful, 1 otherwise.

SEE ALSO
ci, ident, rcs, rcsdiff, rcsintro, rcsmerge, rlog, section .

LIMITATIONS
The option -d gets confused in some circumstances, and accepts no
date before 1970. There is no way to suppress the expansion of
keywords, except by writing them differently.

BUGS
The option -j does not work for files that contain lines with a
single ..