I am attempting to use RCS (Revision Control System) on my XP Home box, but whenever I try to check in any file it gives me the following error: ci: RCS/test.c:1: missing 'head' keyword ci aborted I have searched wide and far for this so-called "head" keyword, but nothing comes up. Is there something I'm doing wrong? Here's the command I enter: C:\rcs\win32>ci -u test.c Most of the people using RCS that I've found have had no problems with this command, but it always and invariably gives me the error whenever I do anything with RCS, even checkout. The error also comes up when I check in empty files. Here's the mirror I got my RCS files from: http://www.cs.purdue.edu/homes/trinkle/RCS/ Should I try to find source code to compile instead of the executables?