NOTE: This section is mainly for use by the main VMD developers, which use RCS to maintain the source code, documentation, and other files. The standard VMD ftp distribution does not include the RCS directory, and the discussions in the manual about RCS do not apply to that case. If you are NOT using RCS, you may simply skip this section and other pertaining to the use RCS when working on VMD.
The Revision Control System (RCS) is used here to allow several people to simultaneously work on modifications to the files used in compiling and running VMD. To do this, each file (i.e., source code files, utility scripts, data or documentation files) is stored in a special RCS format within the directory RCS in the main VMD working directory. Within each subdirectory, a link to this main RCS directory is made, so that there is one single official RCS dir, and several links to it. To obtain a copy of a file, a user checks out the file from RCS. If the file is to be changed, the user must also lock the file when checking it out. When the modifications are complete and verified to be successful, the same user checks the file back in, releasing the lock and depositing the changed version back in the main RCS directory. No other user can lock a file locked by another user until the lock has been released, thus guaranteeing that no two users are attempting to make conflicting changes to the same file simultaneously. Each time a file is modified and checked back in, the current version number of that file is increased; through RCS commands, older versions of a file may be retrieved if new changes end up not working out or are not needed. Several utility programs comprise the RCS system; this section describes the basic use of these programs to perform the tasks mentioned above.
rcs -i -a<username>[,<username>[...]] -L <new files>Each file in the RCS should have a special header which includes special commands to allow RCS to indicate the name, version, and other data in each file when it is checked out; see section 16.3 for notes on what RCS headers to use for each type of file (Latex, shell script, C/C++ source) and where to find standard RCS header examples.
ci -u <new files>
co <list of files>For locked files, when modifications are complete the file should be checked back in, as described next. Files checked out, but not locked, do not need to be checked in.
co -l <list of files>
ci -u <list of checked out files>The -u flag then does an automatic co <files> command, which assures there is a (non-locked) version of the file still in your directory after checking in a file.
rcs -u <file>The first command releases the lock; the others reset the file and check out a copy of the old version (as it existed when initially checked out and locked).
chmod -w <file>