1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
|
<!--startcut ==========================================================-->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<title>Introduction to RCS Issue 20</title>
</HEAD>
<BODY BGCOLOR="#EEE1CC" TEXT="#000000" LINK="#0000FF" VLINK="#0020F0"
ALINK="#FF0000">
<!--endcut ============================================================-->
<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<H2>Introduction to RCS</H2>
<H4>By Hådin Løvdal
<a href="mailto:halovda@krs.hia.no">halovda@krs.hia.no</a></H4>
</center>
<hr>
<P>
Do you find yourself having lots of different unsorted and more or less
old backup files lying around when working on something, but do not dare
to delete any of them because you might need to go back and find out
what changes you have made compared to your current version ?
<P>
Would you like to get all those backups out of the way (without reducing
the number of backups), have them sorted and systemated, and perhaps
even with some sort of documentation like exactly when changes where
made, by who (when several persons are involved), and a few lines that
describes the changes which can be the input of an automatically made
change-log ?
<P>
In that case read on because RCS will do that for you.
<HR>
<P>
Lets have a look at an example (a traditional hello world program)
of what RCS can do:
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>ls -l
total 0
(hlovdal) localhost:/tmp/rcstest>cat > hello.c
/*
* $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $
*
* $Log: rcs.html,v $
* Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
* Imported files
*
*/
main(){
printf("hello world");
}
(hlovdal) localhost:/tmp/rcstest>gcc -o hello hello.c
(hlovdal) localhost:/tmp/rcstest>./hello
hello world(hlovdal) localhost:/tmp/rcstest>ls -l
total 5
-rwxrwx--- 1 hlovdal hlovdal 3928 Jun 28 01:01 hello
-rw-rw---- 1 hlovdal hlovdal 60 Jun 28 01:00 hello.c
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
(The two $-tags in the comment are for automatically documentation, more
about those later)
<P>
Our hello world program works now, so we would like to save it in it's
current state before making any changes to it. This is done by running
ci, Check In, on the source file. That is, the source file is put into
the RCS database. When the file is checked in, it is by default also
removed from the current directory.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>mkdir RCS
(hlovdal) localhost:/tmp/rcstest>ci hello.c
RCS/hello.c,v <-- hello.c
enter description, terminated with single '.' or end of file:
NOTE: This is NOT the log message!
>> A plain simple hello world program
>> .
initial revision: 1.1
done
(hlovdal) localhost:/tmp/rcstest>ls -l
total 5
drwxrwx--- 2 hlovdal hlovdal 1024 Jun 28 01:02 RCS
-rwxrwx--- 1 hlovdal hlovdal 3928 Jun 28 01:01 hello
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
By looking into the RCS directory we can now see that there is a
file with the same name as our program with an extra extension ",v".
(By omitting the RCS directory the file would be in the current directory)
This file now holds the source plus some additional information, and
will later on contain the source for all versions. The rcs file is not
particularly interesting to look at directly:
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>cat RCS/hello.c,v
head 1.1;
access;
symbols;
locks; strict;
comment @ * @;
1.1
date 97.06.28.01.03.43; author hlovdal; state Exp;
branches;
next ;
desc
@A plain simple hello world program
@
1.1
log
@Initial revision
@
text
@/*
* $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $
*
* $Log: rcs.html,v $
* Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
* Imported files
*
*/
main(){
printf("hello world");
}
@
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
This our first version of the hello world program sort of worked, but
it lacks an ending newline and the source isn't pretty. Lets fix that.
The source was moved when it was checked in, so we must use co, Check Out,
to copy the source out of the RCS database.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>co hello.c
RCS/hello.c,v --> hello.c
revision 1.1
done
(hlovdal) localhost:/tmp/rcstest>ls -l
total 6
drwxrwx--- 2 hlovdal hlovdal 1024 Jun 28 01:02 RCS
-rwxrwx--- 1 hlovdal hlovdal 3928 Jun 28 01:01 hello
-r--r----- 1 hlovdal hlovdal 189 Jun 28 01:04 hello.c
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
Note that co by default fetches the source read-only. This is
usually not what we want, so in order to get the source writable we
use the "-l" option to mark the file locked for others.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>co -l hello.c
RCS/hello.c,v --> hello.c
revision 1.1 (locked)
done
(hlovdal) localhost:/tmp/rcstest>ls -l
total 6
drwxrwx--- 2 hlovdal hlovdal 1024 Jun 28 01:02 RCS
-rwxrwx--- 1 hlovdal hlovdal 3928 Jun 28 01:01 hello
-rw-r----- 1 hlovdal hlovdal 197 Jun 28 01:05 hello.c
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
By looking at the hello.c file we see that now some values have been
inserted into $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $ and $Log: rcs.html,v $
inserted into $Id$ and Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
inserted into $Id$ and Imported files
inserted into $Id$ and.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>cat hello.c
/*
* $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $
*
* $Log: rcs.html,v $
* Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
* Imported files
*
* Revision 1.1 1997/06/28 01:03:43 hlovdal
* Initial revision
*
*/
main(){
printf("hello world");
}
(hlovdal) localhost:/tmp/rcstest>vi hello.c
...
</PRE>
<P>
We makes a few changes. Exactly what was changed can be examined with
the program rcsdiff.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>rcsdiff hello.c
===================================================================
RCS file: RCS/hello.c,v
retrieving revision 1.1
diff -r1.1 hello.c
9,10c9,14
< main(){
< printf("hello world");
---
>
> #include <stdio.h>
>
> int main(int argc, char *argv[]){
> printf("hello world\n");
> return 0;
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
The rcsdiff program is just a front end for ordinary diff, so it accepts
all the options to diff, for example "-u".
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>rcsdiff -u hello.c
===================================================================
RCS file: RCS/hello.c,v
retrieving revision 1.1
diff -u -r1.1 hello.c
--- hello.c 1997/06/28 01:03:43 1.1
+++ hello.c 1997/06/28 01:05:21
@@ -6,6 +6,10 @@
* Initial revision
*
*/
-main(){
-printf("hello world");
+
+#include <stdio.h>
+
+int main(int argc, char *argv[]){
+ printf("hello world\n");
+ return 0;
}
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
This version looks good, so we want to save it with Check In. By giving
option "-l", ci runs a implicit "co -l" so that the source file remains
checked out. When ci is run we are asked to enter a log description of
our changes. This log description is inserted into $Log: rcs.html,v $
our changes. This log description is inserted into Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
our changes. This log description is inserted into Imported files
our changes. This log description is inserted into.
<P>
<PRE>
(hlovdal) localhost:/tmp/rcstest>ci -l hello.c
RCS/hello.c,v <-- hello.c
new revision: 1.2; previous revision: 1.1
enter log message, terminated with single '.' or end of file:
>> Fixed main prototype, inserted a missing newline and a missing #include
>> .
done
(hlovdal) localhost:/tmp/rcstest>cat hello.c
/*
* $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $
*
* $Log: rcs.html,v $
* Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
* Imported files
*
* Revision 1.2 1997/06/28 01:07:23 hlovdal
* Fixed main prototype, inserted a missing newline and a missing #include
*
* Revision 1.1 1997/06/28 01:03:43 hlovdal
* Initial revision
*
*/
#include <stdio.h>
int main(int argc, char *argv[]){
printf("hello world\n");
return 0;
}
(hlovdal) localhost:/tmp/rcstest>gcc -o hello hello.c
(hlovdal) localhost:/tmp/rcstest>./hello
hello world
(hlovdal) localhost:/tmp/rcstest>
</PRE>
<P>
<HR>
<H2>
In short RCS is this simple to use:
</H2>
<OL>
<LI>"mkdir RCS"
<LI>Insert $Id: rcs.html,v 1.1.1.1 1997/09/14 15:01:51 schwarz Exp $ and $Log: rcs.html,v $
<LI>Insert $Id$ and Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
<LI>Insert $Id$ and Imported files
<LI>Insert $Id$ and into one comment. Optional, but nice
to have. (NB! Note that $Log: rcs.html,v $
to have. (NB! Note that Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
to have. (NB! Note that Imported files
to have. (NB! Note that does *not* include previous
versions. If $Log: rcs.html,v $
versions. If Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
versions. If Imported files
versions. If is inserted after some time only that
and later versions will end up in the log. It is therefore
smart to have $Log: rcs.html,v $
smart to have Revision 1.1.1.1 1997/09/14 15:01:51 schwarz
smart to have Imported files
smart to have in the file from the start)
<LI>Edit the file
<LI>Optionally run rcsdiff when you want to see what changes
you have made since last check in.
<LI>Run "ci -l" each time you want to save what you have done so far.
<LI>Repeat 3 to 5.
</OL>
<P>
For more info on RCS look at the rcsintro(1) man page.
<P>
Here in this example RCS is used on C source, but RCS can be used on many
other things. Config files in /etc are for example excellent candidates
of being put under RCS control.
<P>
RCS is one method of version control. Two others are SCCS and CVS.
CVS (Concurrent Versions System) is a further development of RCS intended
to be used on larger software projects. For example most (?) BSD clones
are distributed and developed using CVS.
<P>
SCCS (Source Code Control System) is an old proprietary system which few
(if any) uses. I think SCCS and RCS have a somewhat a similar relation
as traditional compress vs gzip.
<P>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright © 1997, Hå Løvdal<BR>
Published in Issue 20 of the Linux Gazette, August 1997</H5></center>
<!--===================================================================-->
<P> <hr> <P>
<A HREF="./lg_toc20.html"><IMG ALIGN=BOTTOM SRC="../gx/indexnew.gif"
ALT="[ TABLE OF CONTENTS ]"></A>
<A HREF="../lg_frontpage.html"><IMG ALIGN=BOTTOM SRC="../gx/homenew.gif"
ALT="[ FRONT PAGE ]"></A>
<A HREF="./sameer.html"><IMG SRC="../gx/back2.gif"
ALT=" Back "></A>
<A HREF="./lyx.html"><IMG SRC="../gx/fwd.gif" ALT=" Next "></A>
<P> <hr> <P>
<!--startcut ==========================================================-->
</BODY>
</HTML>
<!--endcut ============================================================-->
|
