This directory contains complete sources for version 4 of RCS. Version 3 was included in the 4.3 BSD distribution. Features include: 1) Version 4 supports the "branch" keyword. 2) Several bug fixes. In particular dereferencing of NULL pointers has been fixed. Previous versions dumped core on Sun machines. 3) Version 4 is backward compatible with version 3. Version 4 RCS will handle files checked in under version 3 (but not vice versa). 4) This distribution is not supported in anyway. However, bugs and (especially) bug fixes may be reported to rcs-bugs@cs.purdue.edu. 5) Older versions of diff do not support options used by RCS. It is known that 4.3 BSD, and SunOS 3.2 (and later releases) support the needed options. If your version of diff does not support these options, rcsdiff and rcsmerge will fail. Send mail to the above mail list giving the version of Unix you run, and arrangements will be made to distribute diff. 6) See the READ_ME file in the src subdirectory concerning distribution of RCS sources. 7) All sources for RCS are contained in the "src" subdirectory. Read the directions in its Makefile to set up the correct compile options for building RCS on your system. 8) man pages reside in man. 9) Troff source for the paper "RCS A System for Version Control", which