DOT language

DOT is a plain text graph description language. DOT graphs are typically files with the file extension gv or . The extension gv is preferred to avoid confusion with the extension dot used by early (pre-2007) versions of Microsoft Word.

Various programs can process DOT files. Some, such as OmniGraffle, dot, neato, twopi, circo, fdp, and sfdp, can read a DOT file and render it in graphical form. Others, such as gvpr, gc, acyclic, ccomps, sccmap, and tred, read DOT files and perform calculations on the represented graph. Finally, others, such as lefty, dotty, and grappa, provide an interactive interface. The GVedit tool combines a text editor with noninteractive image viewer. Most programs are part of the Graphviz package or use it internally.

At its simplest, DOT can be used to describe an undirected graph. An undirected graph shows simple relations between objects, such as friendship between people. The graph keyword is used to begin a new graph, and nodes are described within curly braces. A double-hyphen (--) is used to show relations between the nodes.

Similar to undirected graphs, DOT can describe directed graphs, such as flowcharts and dependency trees. The syntax is the same as for undirected graphs, except the digraph keyword is used to begin the graph, and an arrow (->) is used to show relationships between nodes.

Various attributes can be applied to graphs, nodes and edges in DOT files. These attributes can control aspects such as color, shape, and line styles. 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). Graph attributes are specified as direct attribute-value pairs under the graph element. Multiple attributes are separated by a comma or using multiple sets of square brackets. Node attributes are placed after a statement containing only the name of the node, and no relations.

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