A "Hello world" program is a computer program that outputs "Hello World" (or some variant) on a display device. The first known version of this program comes from Brian Kernighan's paper A Tutorial Introduction to the Language B from 1972 (chapter 7). In it's first form it was used to show how to use external variables in B but since then it has become pretty much the standard example to show the very basic syntax and most simple program in any given programming language.
Subversion exists to be universally recognized and adopted as an open-source, centralized version control system characterized by its reliability as a safe haven for valuable data; the simplicity of its model and usage; and its ability to support the needs of a wide variety of users and projects, from individuals to large-scale enterprise operations. IANA