Produce device-independent documentation with Groff

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Groff (GNU Troff) is the latest open source implementation of Troff, a document-preparation system that generates print and screen documents for various devices from the same input source. Get an introduction to the Groff system and learn how you can use it for preparing your documentation, help systems, reports, or any printed output where professional quality, portability, and support for multiple output formats are desired.

Link: ibm.com