Category : Miscellaneous Language Source Code
Archive   : RCS56DOS.ZIP

Output of file : RCSINTRO.MAN contained in archive : RCS56DOS.ZIP


rcsintro - introduction to RCS commands

The Revision Control System (RCS) manages multiple
revisions of files. RCS automates the storing, retrieval,
logging, identification, and merging of revisions. RCS is
useful for text that is revised frequently, for example
programs, documentation, graphics, papers, and form

The basic user interface is extremely simple. The novice
only needs to learn two commands: ccii(1) and ccoo(1). ccii,
short for ``check in'', deposits the contents of a file
into an archival file called an RCS file. An RCS file
contains all revisions of a particular file. ccoo, short
for ``check out'', retrieves revisions from an RCS file.

FFuunnccttiioonnss ooff RRCCSS
+o Store and retrieve multiple revisions of text. RCS
saves all old revisions in a space efficient way.
Changes no longer destroy the original, because the
previous revisions remain accessible. Revisions
can be retrieved according to ranges of revision
numbers, symbolic names, dates, authors, and

+o Maintain a complete history of changes. RCS logs
all changes automatically. Besides the text of
each revision, RCS stores the author, the date and
time of check-in, and a log message summarizing the
change. The logging makes it easy to find out what
happened to a module, without having to compare
source listings or having to track down colleagues.

+o Resolve access conflicts. When two or more
programmers wish to modify the same revision, RCS
alerts the programmers and prevents one
modification from corrupting the other.

+o Maintain a tree of revisions. RCS can maintain
separate lines of development for each module. It
stores a tree structure that represents the
ancestral relationships among revisions.

+o Merge revisions and resolve conflicts. Two
separate lines of development of a module can be
coalesced by merging. If the revisions to be
merged affect the same sections of code, RCS alerts
the user about the overlapping changes.

+o Control releases and configurations. Revisions can
be assigned symbolic names and marked as released,
stable, experimental, etc. With these facilities,

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configurations of modules can be described simply
and directly.

+o Automatically identify each revision with name,
revision number, creation time, author, etc. The
identification is like a stamp that can be embedded
at an appropriate place in the text of a revision.
The identification makes it simple to determine
which revisions of which modules make up a given

+o Minimize secondary storage. RCS needs little extra
space for the revisions (only the differences). If
intermediate revisions are deleted, the
corresponding deltas are compressed accordingly.

GGeettttiinngg SSttaarrtteedd wwiitthh RRCCSS
Suppose you have a file that you wish to put under
control of RCS. If you have not already done so, make an
RCS directory with the command

mmkkddiirr RRCCSS

Then invoke the check-in command


This command creates an RCS file in the RRCCSS directory,
stores into it as revision 1.1, and deletes It
also asks you for a description. The description should
be a synopsis of the contents of the file. All later
check-in commands will ask you for a log entry, which
should summarize the changes that you made.

Files in the RCS directory are called RCS files; the
others are called working files. To get back the working
file in the previous example, use the check-out


This command extracts the latest revision from the RCS
file and writes it into If you want to edit, you
must lock it as you check it out with the command

ccoo --ll

You can now edit

Suppose after some editing you want to know what changes
that you have made. The command


GNU 1992/02/17 2


tells you the difference between the most recently
checked-in version and the working file. You can check
the file back in by invoking


This increments the revision number properly.

If ccii complains with the message

ccii eerrrroorr:: nnoo lloocckk sseett bbyy _y_o_u_r _n_a_m_e

then you have tried to check in a file even though you did
not lock it when you checked it out. Of course, it is too
late now to do the check-out with locking, because another
check-out would overwrite your modifications. Instead,

rrccss --ll

This command will lock the latest revision for you, unless
somebody else got ahead of you already. In this case,
you'll have to negotiate with that person.

Locking assures that you, and only you, can check in the
next update, and avoids nasty problems if several people
work on the same file. Even if a revision is locked, it
can still be checked out for reading, compiling, etc. All
that locking prevents is a _c_h_e_c_k_-_i_n by anybody but the

If your RCS file is private, i.e., if you are the only
person who is going to deposit revisions into it, strict
locking is not needed and you can turn it off. If strict
locking is turned off, the owner of the RCS file need not
have a lock for check-in; all others still do. Turning
strict locking off and on is done with the commands

rrccss --UU and rrccss --LL

If you don't want to clutter your working directory with
RCS files, create a subdirectory called RRCCSS in your
working directory, and move all your RCS files there. RCS
commands will look first into that directory to find
needed files. All the commands discussed above will still
work, without any modification. (Actually, pairs of RCS
and working files can be specified in three ways: (a) both
are given, (b) only the working file is given, (c) only
the RCS file is given. Both RCS and working files may
have arbitrary path prefixes; RCS commands pair them up

To avoid the deletion of the working file during check-in
(in case you want to continue editing or compiling),

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ccii --ll or ccii --uu

These commands check in as usual, but perform an
implicit check-out. The first form also locks the checked
in revision, the second one doesn't. Thus, these options
save you one check-out operation. The first form is
useful if you want to continue editing, the second one if
you just want to read the file. Both update the
identification markers in your working file (see below).

You can give ccii the number you want assigned to a checked
in revision. Assume all your revisions were numbered 1.1,
1.2, 1.3, etc., and you would like to start release 2.
The command

ccii --rr22 or ccii --rr22..11

assigns the number 2.1 to the new revision. From then on,
ccii will number the subsequent revisions with 2.2, 2.3,
etc. The corresponding ccoo commands

ccoo --rr22 and ccoo --rr22..11

retrieve the latest revision numbered 2._x and the revision
2.1, respectively. ccoo without a revision number selects
the latest revision on the _t_r_u_n_k, i.e. the highest
revision with a number consisting of two fields. Numbers
with more than two fields are needed for branches. For
example, to start a branch at revision 1.3, invoke

ccii --rr11..33..11

This command starts a branch numbered 1 at revision 1.3,
and assigns the number to the new revision. For
more information about branches, see rrccssffiillee(5).

AAuuttoommaattiicc IIddeennttiiffiiccaattiioonn
RCS can put special strings for identification into your
source and object code. To obtain such identification,
place the marker


into your text, for instance inside a comment. RCS will
replace this marker with a string of the form

$$IIdd:: _f_i_l_e_n_a_m_e _r_e_v_i_s_i_o_n _d_a_t_e _t_i_m_e _a_u_t_h_o_r _s_t_a_t_e

With such a marker on the first page of each module, you
can always see with which revision you are working. RCS
keeps the markers up to date automatically. To propagate

GNU 1992/02/17 4


the markers into your object code, simply put them into
literal character strings. In C, this is done as follows:

ssttaattiicc cchhaarr rrccssiidd[[]] == ""$$IIdd$$"";;

The command iiddeenntt extracts such markers from any file,
even object code and dumps. Thus, iiddeenntt lets you find out
which revisions of which modules were used in a given

You may also find it useful to put the marker $$LLoogg$$ into
your text, inside a comment. This marker accumulates the
log messages that are requested during check-in. Thus,
you can maintain the complete history of your file
directly inside it. There are several additional
identification markers; see ccoo(1) for details.

Author: Walter F. Tichy.
Revision Number: 5.2; Release Date: 1992/02/17.
Copyright 1982, 1988, 1989 by Walter F. Tichy.
Copyright 1990, 1991, 1992 by Paul Eggert.

ci(1), co(1), ident(1), rcs(1), rcsdiff(1), rcsintro(1),
rcsmerge(1), rlog(1)
Walter F. Tichy, RCS--A System for Version Control,
_S_o_f_t_w_a_r_e_-_-_P_r_a_c_t_i_c_e _& _E_x_p_e_r_i_e_n_c_e 1155, 7 (July 1985),

GNU 1992/02/17 5

  3 Responses to “Category : Miscellaneous Language Source Code
Archive   : RCS56DOS.ZIP

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: