Device Control Commands (The GNU Troff Manual)

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6.1.2.4 Device Control Commands

+ +

Each device control command starts with the letter ‘x’, followed by +a space character (optional or arbitrary space or tab in gtroff) +and a subcommand letter or word; each argument (if any) must be preceded +by a syntactical space. All ‘x’ commands are terminated by a +syntactical line break; no device control command can be followed by +another command on the same line (except a comment). +

The subcommand is basically a single letter, but to increase +readability, it can be written as a word, i.e., an arbitrary sequence of +characters terminated by the next tab, space, or newline character. All +characters of the subcommand word but the first are simply ignored. For +example, gtroff outputs the initialization command ‘x i’ +as ‘x init’ and the resolution command ‘x r’ as +‘x res’. +

In the following, the syntax element ‹line break› means a +syntactical line break (see Separation). +

xF name‹line break›

The ‘F’ stands for Filename. +

Use name as the intended name for the current file in error +reports. This is useful for remembering the original file name when +gtroff uses an internal piping mechanism. The input file is not +changed by this command. This command is a gtroff extension. +

xf n s‹line break›

The ‘f’ stands for font. +

Mount font position n (a non-negative integer) with font +named s (a text word). See Font Positions. +

xH n‹line break›

The ‘H’ stands for Height. +

Set glyph height to n (a positive integer in scaled points +‘z’). AT&T troff uses the unit points (‘p’) +instead. See Output Language Compatibility. +

xi‹line break›

The ‘i’ stands for init. +

Initialize device. This is the third command of the prologue. +

xp‹line break›

The ‘p’ stands for pause. +

Parsed but ignored. The AT&T troff manual documents +this command as +

pause device, can be restarted
+

+ +

but GNU troff output drivers do nothing with this command. +

xr n h v‹line break›

The ‘r’ stands for resolution. +

Resolution is n, while h is the minimal horizontal +motion, and v the minimal vertical motion possible with this +device; all arguments are positive integers in basic units ‘u’ per +inch. This is the second command of the prologue. +

xS n‹line break›

The ‘S’ stands for Slant. +

Set slant to n (an integer in basic units ‘u’). +

xs‹line break›

The ‘s’ stands for stop. +

Terminates the processing of the current file; issued as the last +command of any intermediate troff output. +

xt‹line break›

The ‘t’ stands for trailer. +

Generate trailer information, if any. In GNU troff, this is +ignored. +

xT xxx‹line break›

The ‘T’ stands for Typesetter. +

Set the name of the output driver to xxx, a sequence of +non-whitespace characters terminated by whitespace. The possible names +correspond to those of groff’s -T option. This is the +first command of the prologue. +

xu n‹line break›

The ‘u’ stands for underline. +

Configure underlining of spaces. If n is 1, start +underlining of spaces; if n is 0, stop underlining of spaces. +This is needed for the cu request in nroff mode and is +ignored otherwise. This command is a gtroff extension. +

xX anything‹line break›

The ‘x’ stands for X-escape. +

Send string anything uninterpreted to the device. If the line +following this command starts with a ‘+’ character this line is +interpreted as a continuation line in the following sense. The ‘+’ +is ignored, but a newline character is sent instead to the device, the +rest of the line is sent uninterpreted. The same applies to all +following lines until the first character of a line is not a ‘+’ +character. This command is generated by the gtroff escape +sequence \X. The line-continuing feature is a gtroff +extension. +

+ +