Editing Troff (section)

{{Short description|Typesetting language}}
{{about|the Unix document processing system|the command in BASIC|TROFF|the chess grandmaster|Kayden Troff}}
{{Distinguish|Trough (disambiguation)}}
{{Redirect|tbl||TBL (disambiguation)}}
{{lowercase title}}
{{Missing information|short list of books typeset with troff|date=January 2021}}
{{Infobox software
| name                   = troff
| logo                   = 
| screenshot             = 
| screenshot size        = 
| caption                = 
| author                 = [[Joe Ossanna]]
| developer              = [[AT&T Bell Laboratories]]
| released               = 
| latest release version = 
| latest release date    = 
| programming language   = [[C (programming language)|C]]
| operating system       = [[Unix]], [[Unix-like]], [[Plan 9 from Bell Labs|Plan 9]]
| platform               = [[Cross-platform]]
| genre                  = [[Command (computing)|Command]]
| license                = Plan 9: [[MIT License]]
| website                = 
}}
'''troff''' ({{IPAc-en|ˈ|t|iː|r|ɒ|f}}), short for "typesetter roff", is the major component of a [[document processing system]] developed by [[Bell Labs]] for the [[Unix]] operating system. troff and the related [[nroff]] were both developed from the original [[roff (software)|roff]].

While nroff was intended to produce output on terminals and line printers, troff was intended to produce output on [[typesetting]] systems, specifically the [[CAT (phototypesetter)|Graphic Systems CAT]], which had been introduced in 1972. Both used the same underlying [[markup language]], and a single source file could normally be used by nroff or troff without change.

''troff'' features commands to designate fonts, spacing, paragraphs, margins, footnotes and more. Unlike many other text formatters, ''troff'' can position characters arbitrarily on a page, even overlapping them, and has a fully programmable input language. Separate preprocessors are used for more convenient production of tables, diagrams, and mathematics. Inputs to troff are plain text files and can be created by any text editor.

Extensive [[#macros|macro packages]] have been created for various document styles. A typical distribution of '''troff''' includes the '''me''' macros for formatting research papers, '''man''' and '''mdoc''' macros for creating Unix [[UNIX manual|man pages]], '''mv''' macros for creating mountable [[Overhead projector|transparencies]], and the '''ms''' and '''mm''' macros for letters, books, technical memoranda, and reports.