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Files Reference

nroff or troff Input File Format


Specifies input file format for the nroff and troff commands.


The nroff and troff commands format text for printing by interspersing the text with control sequences. Control sequences are either control line requests or escape requests that control text processing by the printing device.

Control lines begin with a control character followed by a one- or two-character name that specifies a basic request or a user-defined macro. Default control characters are the . (dot) or the ' (apostrophe). The ' (apostrophe) control character suppresses the nroff or troff command break function, which is caused by some requests. This break function forces output of a partially filled line. To separate the control character from the request or macro, use white space created with either a tab or the space bar. The nroff and troff commands ignore control lines with unrecognized names.

Escape requests can be inserted anywhere in the input text by means of an escape character. The \ (backslash) character is the default escape character. For example, the escape request \nr causes the contents of the number register, r, to be read.

If text must begin a line with a . (dot), a zero-width character sequence (\&) must precede the control character. This is true even if the control character is preceded by an escape request. The zero-width character prevents the command from interpreting the text as a control character. See the example for an illustration of the use of a zero-width character.


To print the words .dean, enter:


If you neglected to add the \&, the formatter would read the statement as the macro request:

.de an

Related Information

The nroff command, troff command.

The nroff and troff Requests for the nroff and troff Commands.

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