DOT is a graph description language, developed as a part of the Graphviz project.
Others, such as gvpr, gc, acyclic, ccomps, sccmap, and tred, read DOT files and perform calculations on the represented graph.
An undirected graph shows simple relations between objects, such as reciprocal friendship between people.
For nodes and edges, one or more attribute–value pairs are placed in square brackets [] after a statement and before the semicolon (which is optional).
In addition, it ignores lines with a number sign symbol # as their first character, like many interpreted languages.