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| Chapter 12 |

# 12. Nroff and Troff

Contents:
Introduction
Command-line Invocation
Using the Requests: An Overview
Default Operation of Requests
Group Summary of Requests
Alphabetical Summary of Requests
Escape Sequences
Predefined Number Registers
Special Characters

This section presents the following topics:

- Introduction

- Command-line invocation

- Using the requests: an overview

- Default operation of requests

- Group summary of requests

- Alphabetical summary of requests

- Escape sequences

- Predefined number registers

- Special characters

## 12.1 Introduction

Nroff and troff are UNIX programs for formatting text files. Nroff is designed to format output for line printers and letter-quality printers; you can also display the output on your screen. Troff is designed for typesetting. Except for some functions that are specific to typesetting, the same commands work for both programs.

Nroff and troff are not part of standard SVR4 but are included in the compatibility packages. It is this version that is documented here. Note, however, that some UNIX distributors include a vendor-specific version of nroff/troff. Various enhanced packages are also available, such as sqtroff from SoftQuad or groff from the Free Software Foundation. These packages might include additional requests or escape sequences. For completely accurate information, we recommend that you consult the text processing manuals that come with your specific UNIX implementation.

In addition, we make references to ditroff, or device-independent troff, which is a later version of troff. For the most part, ditroff works the same as troff; where there are distinctions, the original troff is referred to as otroff.

11.8 Alphabetical Summary of Commands |  | 12.2 Command-line Invocation