rcsintro.5 (2010 09)

rcsintro(5) rcsintro(5)

• 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.

• Only the RCS ﬁle is given. Then the working ﬁle is assumed to be in the current directory and its

name is derived from the name of the RCS ﬁle by removing path1

/ and the sufﬁx ,v.

• Only the working ﬁle is given. Then the name of the RCS ﬁle is derived from the name of the work-

ing ﬁle by removing path2

/ and appending the sufﬁx

,v.

If the RCS ﬁle name is omitted or speciﬁed without a path, RCS commands look for the RCS ﬁle in the

directory

./RCS (or the directory it points to if it is a directory link), then in the current working direc-

tory.

RCS Directory Links

RCS supports directory links. If a regular ﬁle named RCS exists in the current working directory, RCS

interprets the ﬁrst line as a path name to the directory where RCS ﬁles are stored. RCS can follow a

chain of up to ten directory links to reach the RCS directory.

Automatic Identiﬁcation

RCS can put special strings for identiﬁcation into your source and object code. To obtain such

identiﬁcation, place the marker:

$Header$

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

$Header: ﬁlename revision_number date time author state

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 the markers into your object

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

static char rcsid[] = "$Header$";

The command ident extracts such markers from any ﬁle, even object code and dumps. Thus,

ident

lets you ﬁnd out which revisions of which modules were used in a given program.

You may also ﬁnd it useful to put the marker

$Log$ into your text, inside a comment. This marker accu-

mulates the log messages that are requested during check-in. Thus, you can maintain the complete his-

tory of your ﬁle directly inside it. There are several additional identiﬁcation markers. See co(1) for

details.

WARNINGS

Names of RCS ﬁles are generated by appending

,v to the end of the working ﬁle name. If the resulting

RCS ﬁle name is too long for the ﬁle system on which the RCS ﬁle should reside, the RCS command ter-

minates with an error message.

RCS is designed to be used with TEXT ﬁles only. Attempting to use RCS with nontext (binary) ﬁles will

result in data corruption.

AUTHOR

rcsintro was developed by Walter F. Tichy, Purdue University, West Lafayette, IN 47907, USA.