How to use the command `troff` (with examples)

troff is a typesetting processor for the groff (GNU Troff) document formatting system. It is used to format and typeset documents, allowing users to customize the appearance and layout of text, as well as generate output in different formats such as PostScript, ASCII text, and PDF.

Use case 1: Format output for a PostScript printer, saving the output to a file

Code:

troff path/to/input.roff | grops > path/to/output.ps

Motivation: The motivation for using this example is to format the input document in .roff format and convert it into PostScript format suitable for printing. Saving the output to a file allows for easy distribution or further processing.

Explanation:

• troff is the command itself, which is invoked to format the input file.
• path/to/input.roff is the path to the input file that needs to be formatted.
• grops is a program that takes the output generated by troff and converts it into PostScript format.
• > path/to/output.ps redirects the output of grops to the specified file, saving it as a PostScript document.

Example output: The output of this command will be a formatted PostScript document saved at the specified output path.

Use case 2: Format output for a PostScript printer using the [me] macro package, saving the output to a file

Code:

troff -me path/to/input.roff | grops > path/to/output.ps

Motivation: This example is useful when formatting documents using the [me] macro package, which is specifically designed for writing technical documentation or manuals.

Explanation:

• troff -me specifies the me macro package to be used for formatting the document.
• path/to/input.roff is the path to the input file that needs to be formatted.
• grops is a program that takes the output generated by troff and converts it into PostScript format.
• > path/to/output.ps redirects the output of grops to the specified file, saving it as a PostScript document.

Example output: The output of this command will be a formatted PostScript document saved at the specified output path.

Use case 3: Format output as [a]SCII text using the [man] macro package

Code:

troff -T ascii -man path/to/input.roff | grotty

Motivation: This use case is helpful when formatting a document using the [man] macro package and rendering it as ASCII text. This format is commonly used for text-based browsers or terminal output.

Explanation:

• troff -T ascii specifies the output format as ASCII text.
• -man specifies the [man] macro package to be used for formatting the document.
• path/to/input.roff is the path to the input file that needs to be formatted.
• grotty is a program that takes the ASCII output generated by troff and renders it for display.

Example output: The output of this command will be the formatted document rendered as ASCII text in the terminal.

Use case 4: Format output as a [pdf] file, saving the output to a file

Code:

troff -T pdf path/to/input.roff | gropdf > path/to/output.pdf

Motivation: Sometimes it is necessary to generate a PDF document directly from the formatted output, without the need for PostScript as an intermediate format. This use case enables the creation of PDF documents from troff.

Explanation:

• troff -T pdf specifies the output format as PDF.
• path/to/input.roff is the path to the input file that needs to be formatted.
• gropdf is a program that takes the PDF output generated by troff and saves it to a file.
• > path/to/output.pdf redirects the output of gropdf to the specified file, saving it as a PDF document.

Example output: The output of this command will be a formatted PDF document saved at the specified output path.

Conclusion:

The troff command provides a powerful tool for formatting and typesetting documents. Its versatility allows for output in various formats such as PostScript, ASCII, and PDF, providing flexibility for different use cases. Whether it is generating printer-friendly output, rendering documents as ASCII text, or creating PDF documents, troff proves to be a valuable command for document processing.