1CO(1) General Commands Manual CO(1)
2
6 co - check out RCS revisions
7
9 co [options] file ...
10
12 co retrieves a revision from each RCS file and stores it into the cor‐
13 responding working file.
14 Filenames matching an RCS suffix denote RCS files; all others denote
16 working files. Names are paired as explained in ci(1).
17 Revisions of an RCS file can be checked out locked or unlocked. Lock‐
19 ing a revision prevents overlapping updates. A revision checked out
20 for reading or processing (e.g., compiling) need not be locked. A re‐
21 vision checked out for editing and later checkin must normally be
22 locked. Checkout with locking fails if the revision to be checked out
23 is currently locked by another user. (A lock can be broken with
24 rcs(1).) Checkout with locking also requires the caller to be on the
25 access list of the RCS file, unless he is the owner of the file or the
26 superuser, or the access list is empty. Checkout without locking is
27 not subject to accesslist restrictions, and is not affected by the
28 presence of locks.
29 A revision is selected by options for revision or branch number,
31 checkin date/time, author, or state. When the selection options are
32 applied in combination, co retrieves the latest revision that satisfies
33 all of them. If none of the selection options is specified, co re‐
34 trieves the latest revision on the default branch (normally the trunk,
35 see the -b option of rcs(1)). A revision or branch number can be at‐
36 tached to any of the options -f, -I, -l, -M, -p, -q, -r, or -u. The
37 options -d (date), -s (state), and -w (author) retrieve from a single
38 branch, the selected branch, which is either specified by one of -f,
39 ..., -u, or the default branch.
40 A co command applied to an RCS file with no revisions creates a zero-
42 length working file. co always performs keyword substitution (see be‐
43 low).
44
46 -r[rev]
47 retrieves the latest revision whose number is less than or equal
48 to rev. If rev indicates a branch rather than a revision, the
49 latest revision on that branch is retrieved. If rev is omitted,
50 the latest revision on the default branch (see the -b option of
51 rcs(1)) is retrieved. If rev is $, co determines the revision
52 number from keyword values in the working file. Otherwise, a
53 revision is composed of one or more numeric or symbolic fields
54 separated by periods. If rev begins with a period, then the de‐
55 fault branch (normally the trunk) is prepended to it. If rev is
56 a branch number followed by a period, then the latest revision
57 on that branch is used. The numeric equivalent of a symbolic
58 field is specified with the -n option of the commands ci(1) and
59 rcs(1).
60 -l[rev]
62 same as -r, except that it also locks the retrieved revision for
63 the caller.
64 -u[rev]
66 same as -r, except that it unlocks the retrieved revision if it
67 was locked by the caller. If rev is omitted, -u retrieves the
68 revision locked by the caller, if there is one; otherwise, it
69 retrieves the latest revision on the default branch.
70 -f[rev]
72 forces the overwriting of the working file; useful in connection
73 with -q. See also FILE MODES below.
74 -kkv Generate keyword strings using the default form, e.g. $Revision:
76 5.10.1 $ for the Revision keyword. A locker's name is inserted
77 in the value of the Header, Id, and Locker keyword strings only
78 as a file is being locked, i.e. by ci -l and co -l. This is the
79 default.
80 -kkvl Like -kkv, except that a locker's name is always inserted if the
82 given revision is currently locked.
83 -kk Generate only keyword names in keyword strings; omit their val‐
85 ues. See KEYWORD SUBSTITUTION below. For example, for the Re‐
86 vision keyword, generate the string $Revision$ instead of $Revi‐
87 sion: 5.10.1 $. This option is useful to ignore differences due
88 to keyword substitution when comparing different revisions of a
89 file. Log messages are inserted after $Log$ keywords even if
90 -kk is specified, since this tends to be more useful when merg‐
91 ing changes.
92 -ko Generate the old keyword string, present in the working file
94 just before it was checked in. For example, for the Revision
95 keyword, generate the string $Revision: 1.1 $ instead of $Revi‐
96 sion: 5.10.1 $ if that is how the string appeared when the file
97 was checked in. This can be useful for file formats that cannot
98 tolerate any changes to substrings that happen to take the form
99 of keyword strings.
100 -kb Generate a binary image of the old keyword string. This acts
102 like -ko, except it performs all working file input and output
103 in binary mode. This makes little difference on Posix and Unix
104 hosts, but on DOS-like hosts one should use rcs -i -kb to ini‐
105 tialize an RCS file intended to be used for binary files. Also,
106 on all hosts, rcsmerge(1) normally refuses to merge files when
107 -kb is in effect.
108 -kv Generate only keyword values for keyword strings. For example,
110 for the Revision keyword, generate the string 5.10.1 instead of
111 $Revision: 5.10.1 $. This can help generate files in program‐
112 ming languages where it is hard to strip keyword delimiters like
113 $Revision: $ from a string. However, further keyword substitu‐
114 tion cannot be performed once the keyword names are removed, so
115 this option should be used with care. Because of this danger of
116 losing keywords, this option cannot be combined with -l, and the
117 owner write permission of the working file is turned off; to
118 edit the file later, check it out again without -kv.
119 -p[rev]
121 prints the retrieved revision on the standard output rather than
122 storing it in the working file. This option is useful when co
123 is part of a pipe.
124 -q[rev]
126 quiet mode; diagnostics are not printed.
127 -I[rev]
129 interactive mode; the user is prompted and questioned even if
130 the standard input is not a terminal.
131 -ddate retrieves the latest revision on the selected branch whose
133 checkin date/time is less than or equal to date. The date and
134 time can be given in free format. The time zone LT stands for
135 local time; other common time zone names are understood. For
136 example, the following dates are equivalent if local time is
137 January 11, 1990, 8pm Pacific Standard Time, eight hours west of
138 Coordinated Universal Time (UTC):
139 8:00 pm lt
141 4:00 AM, Jan. 12, 1990 default is UTC
142 1990-01-12 04:00:00+00 ISO 8601 (UTC)
143 1990-01-11 20:00:00-08 ISO 8601 (local time)
144 1990/01/12 04:00:00 traditional RCS format
145 Thu Jan 11 20:00:00 1990 LT output of ctime(3) + LT
146 Thu Jan 11 20:00:00 PST 1990 output of date(1)
147 Fri Jan 12 04:00:00 GMT 1990
148 Thu, 11 Jan 1990 20:00:00 -0800 Internet RFC 822
149 12-January-1990, 04:00 WET
150 Most fields in the date and time can be defaulted. The default
152 time zone is normally UTC, but this can be overridden by the -z
153 option. The other defaults are determined in the order year,
154 month, day, hour, minute, and second (most to least signifi‐
155 cant). At least one of these fields must be provided. For
156 omitted fields that are of higher significance than the highest
157 provided field, the time zone's current values are assumed. For
158 all other omitted fields, the lowest possible values are as‐
159 sumed. For example, without -z, the date 20, 10:30 defaults to
160 10:30:00 UTC of the 20th of the UTC time zone's current month
161 and year. The date/time must be quoted if it contains spaces.
162 -M[rev]
164 Set the modification time on the new working file to be the date
165 of the retrieved revision. Use this option with care; it can
166 confuse make(1).
167 -sstate
169 retrieves the latest revision on the selected branch whose state
170 is set to state.
171 -S Enable self-same mode. In this mode, the owner of a lock is
173 unimportant, just that it exists. Effectively, this means the
174 user cannot check out the same revision twice.
175 -T Preserve the modification time on the RCS file even if the RCS
177 file changes because a lock is added or removed. This option
178 can suppress extensive recompilation caused by a make(1) depen‐
179 dency of some other copy of the working file on the RCS file.
180 Use this option with care; it can suppress recompilation even
181 when it is needed, i.e. when the change of lock would mean a
182 change to keyword strings in the other working file.
183 -w[login]
185 retrieves the latest revision on the selected branch which was
186 checked in by the user with login name login. If the argument
187 login is omitted, the caller's login is assumed.
188 -jjoinlist
190 generates a new revision which is the join of the revisions on
191 joinlist. This option is largely obsoleted by rcsmerge(1) but
192 is retained for backwards compatibility.
193 The joinlist is a comma-separated list of pairs of the form
195 rev2:rev3, where rev2 and rev3 are (symbolic or numeric) revi‐
196 sion numbers. For the initial such pair, rev1 denotes the revi‐
197 sion selected by the above options -f, ..., -w. For all other
198 pairs, rev1 denotes the revision generated by the previous pair.
199 (Thus, the output of one join becomes the input to the next.)
200 For each pair, co joins revisions rev1 and rev3 with respect to
202 rev2. This means that all changes that transform rev2 into rev1
203 are applied to a copy of rev3. This is particularly useful if
204 rev1 and rev3 are the ends of two branches that have rev2 as a
205 common ancestor. If rev1<rev2<rev3 on the same branch, joining
206 generates a new revision which is like rev3, but with all
207 changes that lead from rev1 to rev2 undone. If changes from
208 rev2 to rev1 overlap with changes from rev2 to rev3, co reports
209 overlaps as described in merge(1).
210 For the initial pair, rev2 can be omitted. The default is the
212 common ancestor. If any of the arguments indicate branches, the
213 latest revisions on those branches are assumed. The options -l
214 and -u lock or unlock rev1.
215 -V Print RCS's version number.
217 -Vn Emulate RCS version n, where n can be 3, 4, or 5. This can be
219 useful when interchanging RCS files with others who are running
220 older versions of RCS. To see which version of RCS your corre‐
221 spondents are running, have them invoke rcs -V; this works with
222 newer versions of RCS. If it doesn't work, have them invoke
223 rlog on an RCS file; if none of the first few lines of output
224 contain the string branch: it is version 3; if the dates' years
225 have just two digits, it is version 4; otherwise, it is version
226 5. An RCS file generated while emulating version 3 loses its
227 default branch. An RCS revision generated while emulating ver‐
228 sion 4 or earlier has a time stamp that is off by up to 13
229 hours. A revision extracted while emulating version 4 or ear‐
230 lier contains abbreviated dates of the form yy/mm/dd and can
231 also contain different white space and line prefixes in the sub‐
232 stitution for $Log$.
233 -xsuffixes
235 Use suffixes to characterize RCS files. See ci(1) for details.
236 -zzone specifies the date output format in keyword substitution, and
238 specifies the default time zone for date in the -ddate option.
239 The zone should be empty, a numeric UTC offset, or the special
240 string LT for local time. The default is an empty zone, which
241 uses the traditional RCS format of UTC without any time zone in‐
242 dication and with slashes separating the parts of the date; oth‐
243 erwise, times are output in ISO 8601 format with time zone indi‐
244 cation. For example, if local time is January 11, 1990, 8pm Pa‐
245 cific Standard Time, eight hours west of UTC, then the time is
246 output as follows:
247 option time output
249 -z 1990/01/12 04:00:00 (default)
250 -zLT 1990-01-11 20:00:00-08
251 -z+05:30 1990-01-12 09:30:00+05:30
252 The -z option does not affect dates stored in RCS files, which
254 are always UTC.
255
257 Strings of the form $keyword$ and $keyword:...$ embedded in the text
258 are replaced with strings of the form $keyword:value$ where keyword and
259 value are pairs listed below. Keywords can be embedded in literal
260 strings or comments to identify a revision.
261 Initially, the user enters strings of the form $keyword$. On checkout,
263 co replaces these strings with strings of the form $keyword:value$. If
264 a revision containing strings of the latter form is checked back in,
265 the value fields will be replaced during the next checkout. Thus, the
266 keyword values are automatically updated on checkout. This automatic
267 substitution can be modified by the -k options.
268 Keywords and their corresponding values:
270 $Author$
272 The login name of the user who checked in the revision.
273 $Date$ The date and time the revision was checked in. With -zzone a
275 numeric time zone offset is appended; otherwise, the date is
276 UTC.
277 $Header$
279 A standard header containing the full RCS file name, the revi‐
280 sion number, the date and time, the author, the state, and the
281 locker (if locked). With -zzone a numeric time zone offset is
282 appended to the date; otherwise, the date is UTC.
283 $Id$ Same as $Header$, except that the RCS file name is without the
285 directory components.
286 $Locker$
288 The login name of the user who locked the revision (empty if not
289 locked).
290 $Log$ The log message supplied during checkin, preceded by a header
292 containing the RCS file name, the revision number, the author,
293 and the date and time. With -zzone a numeric time zone offset
294 is appended; otherwise, the date is UTC. Existing log messages
295 are not replaced. Instead, the new log message is inserted af‐
296 ter $Log:...$. This is useful for accumulating a complete
297 change log in a source file.
298 Each inserted line is prefixed by the string that prefixes the
300 $Log$ line. For example, if the $Log$ line is “// $Log:
301 tan.cc $”, RCS prefixes each line of the log with “// ”. This
302 is useful for languages with comments that go to the end of the
303 line. The convention for other languages is to use a “ ∗ ” pre‐
304 fix inside a multiline comment. For example, the initial log
305 comment of a C program conventionally is of the following form:
306 /∗
308 ∗ $Log$
309 ∗/
310 For backwards compatibility with older versions of RCS, if the
312 log prefix is /∗ or (∗ surrounded by optional white space, in‐
313 serted log lines contain a space instead of / or (; however,
314 this usage is obsolescent and should not be relied on.
315 $Name$ The symbolic name used to check out the revision, if any. For
317 example, co -rJoe generates $Name: Joe $. Plain co generates
318 just $Name: $.
319 $RCSfile$
321 The RCS file name without directory components.
322 $Revision$
324 The revision number assigned to the revision.
325 $Source$
327 The full RCS file name.
328 $State$
330 The state assigned to the revision with the -s option of rcs(1)
331 or ci(1).
332 The following characters in keyword values are represented by escape
334 sequences to keep keyword strings well-formed.
335 char escape sequence
337 tab \t
338 newline \n
339 space \040
340 $ \044
341 \ \\
342
344 The working file inherits the read and execute permissions from the RCS
345 file. In addition, the owner write permission is turned on, unless -kv
346 is set or the file is checked out unlocked and locking is set to strict
347 (see rcs(1)).
348 If a file with the name of the working file exists already and has
350 write permission, co aborts the checkout, asking beforehand if possi‐
351 ble. If the existing working file is not writable or -f is given, the
352 working file is deleted without asking.
353
355 co accesses files much as ci(1) does, except that it does not need to
356 read the working file unless a revision number of $ is specified.
357
359 RCSINIT
360 Options prepended to the argument list, separated by spaces. A
361 backslash escapes spaces within an option. The RCSINIT options
362 are prepended to the argument lists of most RCS commands. Use‐
363 ful RCSINIT options include -q, -V, -x, and -z.
364 RCS_MEM_LIMIT
366 Normally, for speed, commands either memory map or copy into
367 memory the RCS file if its size is less than the memory-limit,
368 currently defaulting to ``unlimited''. Otherwise (or if the
369 initially-tried speedy ways fail), the commands fall back to us‐
370 ing standard i/o routines. You can adjust the memory limit by
371 setting RCS_MEM_LIMIT to a numeric value lim (measured in kilo‐
372 bytes). An empty value is silently ignored. As a side effect,
373 specifying RCS_MEM_LIMIT inhibits fall-back to slower routines.
374 TMPDIR Name of the temporary directory. If not set, the environment
376 variables TMP and TEMP are inspected instead and the first value
377 found is taken; if none of them are set, a host-dependent de‐
378 fault is used, typically /tmp.
379
381 The RCS file name, the working file name, and the revision number re‐
382 trieved are written to the diagnostic output. The exit status is zero
383 if and only if all operations were successful.
384
386 Author: Walter F. Tichy.
387 Manual Page Revision: 5.10.1; Release Date: 2023-07-21.
388 Copyright © 2010-2022 Thien-Thi Nguyen.
389 Copyright © 1990, 1991, 1992, 1993, 1994, 1995 Paul Eggert.
390 Copyright © 1982, 1988, 1989 Walter F. Tichy.
391
393 ci(1), ctime(3), date(1), ident(1), make(1), rcs(1), rcsclean(1), rcsd‐
394 iff(1), rcsmerge(1), rlog(1), rcsfile(5).
395 Walter F. Tichy, RCS--A System for Version Control, Software--Practice
397 & Experience 15, 7 (July 1985), 637-654.
398 The full documentation for RCS is maintained as a Texinfo manual. If
400 the info(1) and RCS programs are properly installed at your site, the
401 command
402 info rcs
404 should give you access to the complete manual. Additionally, the RCS
406 homepage:
407 http://www.gnu.org/software/rcs/
409 has news and links to the latest release, development site, etc.
411
413 Links to the RCS and working files are not preserved.
414 There is no way to selectively suppress the expansion of keywords, ex‐
416 cept by writing them differently. In nroff and troff, this is done by
417 embedding the null-character \& into the keyword.
418GNU RCS 5.10.1 2023-07-21 CO(1)