The other cost is the inability of interactive input, but you can use a file to represent keyboard input. To submit a job to NQS, you write a shell script and tell NQS on a given machine to execute this script. Often this script will be trivial, e.g., just the name of an individual executable program. The make command allows the programmer to maintain, update, and regenerate groups of computer programs. This can greatly increase the efficiency of compiling large projects which have multiple source files linked together.
Revision control is a system of keeping track of source file changes and archiving.
One simple revision control system that many people use is to simply make backup copies of their source files. This can be an effective procedure for small projects, but is not efficient with respect to disk space and requires manual documentation of changes. These two products are both available on the SGI machines and you can get GNU RCS for many other platforms. If you would like to read more about the differences, try the Unix FAQ For more information on using RCS, read the rcsintro man page. Note that a revision control system can be used with an document, including TeX files, in addition to programs.