Unix in a Nutshell, 4th Edition

Conceptual Overview

This section provides a brief overview of how to prepare input for nroff and troff. It presents the following topics:

• Requests and macros

• Common requests

• Specifying measurements

• Requests that cause a line break

• Embedded formatting controls

Requests and macros

Formatting is specified by embedding brief codes (called requests) into the text source file. These codes act as directives to nroff and troff when they run. For example, to center a line of text, type the following code in a file:

    .ce
    This text should be centered.

When formatted, the output appears centered:

                    This text should be centered.

There are two types of formatting codes:

• Requests, which provide the most elementary instructions

• Macros, which are predefined combinations of requests

Requests, also known as primitives, allow direct control of almost any feature of page layout and formatting. Macros combine requests to create a total effect. In a sense, requests are like statements, and macros are like functions.

All nroff/troff requests are two-letter lowercase names. Macros are usually upper- or mixed-case names. GNU troff removes the two-character restriction on the length of names.

Specifying measurements

With some requests, the numeric argument can be followed by a scale indicator that specifies a unit of measurement. The valid indicators and their meanings are listed in the following table. Note that all measurements are internally converted to basic units (this conversion is shown in the last column). A basic ...