--- name: "troff" section: "1" platform: "linux" package: "groff" version: "1.24.2-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/troff" --- # troff(1) GNU roff typesetter and document formatter ## Name troff - GNU *roff* typesetter and document formatter ## Synopsis **troff** \[**-abcCEiRSUz**\] \[**-d** *ctext*\] \[**-d** *string***=** *text*\] \[**-f** *font-family*\] \[**-F** *font-directory*\] \[**-I** *inclusion-directory*\] \[**-m** *macro-package*\] \[**-M** *macro-directory*\] \[**-n** *page-number*\] \[**-o** *page-list*\] \[**-r** *cnumeric-expression*\] \[**-r** *register***=** *numeric-expression*\] \[**-T** *output-device*\] \[**-w** *warning-category*\] \[**-W** *warning-category*\] \[*file* ...\] **troff** **--help** **troff** **-v** **troff** **--version** ## Description GNU *troff* transforms [*groff*(7)](/groff/7.md) language input into the device-independent page description language detailed in [*groff\_out*(5)](/groff_out/5.md); *troff* is thus the heart of the GNU *roff* document formatting system. If no *file* operands are present, or if *file* is “**-**”, *troff* reads the standard input stream. GNU *troff* is functionally compatible with the AT&T *troff* typesetter and features numerous extensions. Many people prefer to use the [*groff*(1)](/groff/1.md) command, a front end which also runs preprocessors and output drivers in the appropriate order and with appropriate options. ## Options **-h** and **--help** display a usage message, while **-v** and **--version** show version information; all exit afterward. - **-a** Generate a plain text approximation of the typeset output. The read-only register **.A** is set to 1. This option produces a sort of abstract preview of the formatted output. - • Page breaks are marked by a phrase in angle brackets; for example, “\”. - • Lines are broken where they would be in formatted output. - • Vertical motion, apart from that implied by a break, is not represented. - • A horizontal motion of any size is represented as one space. Adjacent horizontal motions are not combined. Supplemental inter-sentence space (configured by the second argument to the **.ss** request) is not represented. - • A special character is rendered as its identifier between angle brackets; for example, a hyphen appears as “\”. - The above description should not be considered a specification; the details of **-a** output are subject to change. - **-b** Write a backtrace reporting the state of *troff*'s input parser to the standard error stream with each diagnostic message. The line numbers given in the backtrace might not always be correct, because *troff*'s idea of line numbers can be confused by requests that append to macros. - **-c** Disable multi-color output and “**color**” request's ability to enable it. - **-C** Enable AT&T *troff* compatibility mode; implies **-c**. See [*groff\_diff*(7)](/groff_diff/7.md). - **-d** *ctext* **-d** *string***=***text* Define *roff* string *c* or *string* as *text.* *c* must be a one-character identifier; *string* can be of arbitrary length. Such assignments happen before any macro file is loaded, including the startup file. Due to [*getopt\_long*(3)](/getopt_long/3.md) limitations, *c* cannot be, and *string* cannot contain, an equals sign, even though that is a valid character in a *roff* identifier. - **-E** Inhibit *troff* error messages; implies **-Ww**. This option does *not* suppress messages sent to the standard error stream by documents or macro packages using **tm** or related requests. - **-f** *fam* Use *fam* as the default font family. - **-F** *dir* Search in directory *dir* for the selected output device's directory of device and font description files. See the description of *GROFF\_FONT\_PATH* in section “Environment” below for the default search locations and ordering. - **-i** Read the standard input stream after all named input files have been processed. - **-I** *dir* Search the directory *dir* for files (those named on the command line; in **psbb**, **so**, and **soquiet** requests; and in “**\\X'ps: import'**”, “**\\X'ps: file'**”, and “**\\X'pdf: pdfpic'**” device extension escape sequences). **-I** may be specified more than once; each *dir* is searched in the given order. To search the current working directory before others, add “**-I .**” at the desired place; it is otherwise searched last. **-I** works similarly to, and is named for, the “include” option of Unix C compilers. - **-m** *mac* Search for the macro package mac*.tmac* and read it prior to any input. If not found, *tmac.*mac is attempted. See the description of *GROFF\_TMAC\_PATH* in section “Environment” below for the default search locations and ordering. - **-M** *dir* Search directory *dir* for macro files. See the description of *GROFF\_TMAC\_PATH* in section “Environment” below for the default search locations and ordering. - **-n** *num* Begin numbering pages at *num.* The default is **1**. - **-o** *list* Output only pages in *list,* which is a comma-separated list of inclusive page ranges; *n* means page *n,* *m***-***n* means every page between *m* and *n*, **-***n* means every page up to *n*, and *n***-** means every page from *n* on. *troff* stops processing and exits after formatting the last page enumerated in *list.* - **-r** *cnumeric-expression* **-r** *register***=***numeric-expression* Define *roff* register *c* or *register* as *numeric-expression.* *c* must be a one-character identifier; *register* can be of arbitrary length. Such assignments happen before any macro file is loaded, including the startup file. Due to [*getopt\_long*(3)](/getopt_long/3.md) limitations, *c* cannot be, and *register* cannot contain, an equals sign, even though that is a valid character in a *roff* identifier. - **-R** Prevent loading of *troffrc* and *troffrc-end*; this option can be useful for troubleshooting. - **-S** Enable safer mode and ignore any subsequent **-U** option. - **-T** *dev* Prepare output for device *dev.* The default is **ps**; see [*groff*(1)](/groff/1.md). - **-U** Operate in *unsafe mode,* enabling the **cf**, **open**, **opena**, **pi**, **pso**, and **sy** requests, which are disabled by default because they allow an untrusted input document to run arbitrary commands, put arbitrary content into *troff* output, or write to arbitrary file names. (GNU *troff* does not, however, accept newlines (line feeds) in file names supplied as arguments to requests.) This option also adds the current directory to the macro package search path; see the **-m** and **-M** options above. - **-w** *cat* **-W** *cat* Enable and inhibit, respectively, warnings in category *cat.* See section “Warnings” below. - **-z** Suppress formatted output. ## Warnings GNU *troff* divides its warning diagnostics into named, numbered categories. The **-w** and **-W** options use the associated names. A power of two characterizes each category; the **warn** request and the **.warn** register respectively set and report the sum of enabled category codes. Warnings of each category are produced under the following circumstances. | | | | | | | | --- | --- | --- | --- | --- | --- | | Bit | Code | Category | Bit | Code | Category | | 0 | *1* | **char** | 10 | *1024* | **reg** | | 1 | *2* | ***unused*** | 11 | *2048* | **tab** | | 2 | *4* | **break** | 12 | *4096* | ***unused*** | | 3 | *8* | **delim** | 13 | *8192* | **missing** | | 4 | *16* | ***unused*** | 14 | *16384* | **input** | | 5 | *32* | **scale** | 15 | *32768* | **escape** | | 6 | *64* | **range** | 16 | *65536* | **space** | | 7 | *128* | **syntax** | 17 | *131072* | **font** | | 8 | *256* | **di** | 18 | *262144* | **ig** | | 9 | *512* | **mac** | 19 | *524288* | **color** | | | | | 20 | *1048576* | **file** | | | | | | --- | --- | --- | | **break** | 4 | A filled output line could not be broken such that its length was less than or equal to, or adjusted such that its length was exactly equal to, the output line length “**\\n\[.l\]**”. GNU *troff " GNU* reports the amount of overset or underset in the scaling unit configured by the **warnscale** request in **troff " mode** mode, and in ens (‘**n**’; character cells) in **nroff " mode** mode. This category is enabled by default. | | **char** | 1 | No user-defined character of the requested name or index exists and no mounted font defines a glyph for it, or input could not be encoded for device-independent output. This category is enabled by default. | | **color** | 524288 | An undefined color name was selected, an attempt was made to define a color using an unrecognized color space, an invalid channel value in a color definition was encountered, or an attempt was made to redefine a default color. | | **delim** | 8 | The selected delimiter character was ambiguous because it is also meaningful when beginning a numeric expression, or the closing delimiter in an escape sequence was missing or mismatched. A future *groff* release may reject ambiguous delimiters. In compatibility mode, ambiguous delimiters are accepted without warning. | | **di** | 256 | A **di**, **da**, **box**, or **boxa** request was invoked without an argument when there was no current diversion. | | **escape** | 32768 | An unsupported escape sequence was encountered. | | **file** | 1048576 | An attempt was made to read a file that does not exist. or a stream remained open at formatter exit. This category is enabled by default. | | **font** | 131072 | A non-existent font was selected. This category is enabled by default. | | **ig** | 262144 | An invalid escape sequence occurred in input ignored using the **ig** request. This warning category diagnoses a condition that is an error when it occurs in non-ignored input. | | **input** | 16384 | An invalid character occurred on the input stream. | | **mac** | 512 | An undefined string, macro, or diversion was used. When such an object is dereferenced, an empty one of that name is automatically created. So, unless it is later deleted, *troff* issues at most one warning for each. *troff* also uses this category to warn of an attempt to move an unplanted trap macro. In such cases, the unplanted macro is *not* dereferenced, so it is not created if it does not exist. | | **missing** | 8192 | A request was invoked with a mandatory argument absent. | | **range** | 64 | A numeric expression was out of range for its context. | | **reg** | 1024 | An undefined register was used. When an undefined register is dereferenced, the formatter automatically defines it with a value of 0. So, unless it is later deleted, GNU *troff " GNU* issues at most one warning for each. | | **scale** | 32 | A scaling unit inappropriate to its context was used in a numeric expression. | | **space** | 65536 | A space was missing between a request or macro and its argument. This warning is produced when an undefined name longer than two characters is encountered and the first two characters of the name constitute a defined name. No request is invoked, no macro called, and an empty macro is not defined. This category is enabled by default. It never occurs in compatibility mode. | | **syntax** | 128 | A self-contradictory hyphenation mode or character flags were requested; an empty or incomplete numeric expression was encountered; an operand to a numeric operator was missing; an attempt was made to format characters or spaces on an input line after an output line continuation escape sequence; a recognized but inapposite escape sequence or unprintable character code was used in a device extension command; an attempt was made to define a recursive, empty, or nonsensical character class; or a *groff* extension escape sequence or conditional expression operator was used while in compatibility mode. | | **tab** | 2048 | A tab character appeared in a parameterized escape sequence, in an unquoted macro argument, or where a request expected a numeric expression argument. | Two warning names group other warning categories for convenience. - **all** All warning categories except **di**, **mac**, and **reg**. This shorthand is intended to produce all warnings that are useful with macro packages and documents written for AT&T *troff* and its descendants, which have less fastidious diagnostics than GNU *troff*. - **w** All warning categories. Authors of documents and macro packages targeting *groff* are encouraged to use this setting. ## Exit status *troff* exits with status **0** on successful operation, status **2** if the program cannot interpret its command-line arguments, and status **1** if it encounters a fatal error during operation, or is directed to abort by the input. ## Environment *GROFF\_FONT\_PATH* and *GROFF\_TMAC\_PATH* each accept a search path of directories; that is, a list of directory names separated by the system's path component separator character. On Unix systems, this character is a colon (:); on Windows systems, it is a semicolon (;). - *GROFF\_FONT\_PATH* A list of directories in which to seek the selected output device's directory of device and font description files. *troff* will scan directories given as arguments to any specified **-F** options before these, then in a site-specific directory (*/usr/share/groff/site-font*), a standard location (*/usr/share/groff/1.24.2/font*), and a compatibility directory (*/usr/lib/font*) after them. - *GROFF\_TMAC\_PATH* A list of directories in which to search for macro files. *troff* will scan directories given as arguments to any specified **-M** options before these, then the current directory (only if in unsafe mode), the user's home directory, a site-specific directory (*/usr/share/groff/site-tmac*), and a standard location (*/usr/share/groff/1.24.2/tmac*) after them. - *GROFF\_TYPESETTER* Set the default output device. If empty or not set, **ps** is used. The **-T** option overrides *GROFF\_TYPESETTER*. - *SOURCE\_DATE\_EPOCH* A timestamp (expressed as seconds since the Unix epoch) to use as the output creation timestamp in place of the current time. The time is converted to human-readable form using [*gmtime*(3)](/gmtime/3.md) and [*asctime*(3)](/asctime/3.md) when the formatter starts up and stored in registers usable by documents and macro packages. - *TZ* The time zone to use when converting the current time to human-readable form; see [*tzset*(3)](/tzset/3.md). If *SOURCE\_DATE\_EPOCH* is used, it is always converted to human-readable form using UTC. ## Files - */usr/share/groff/1.24.2/tmac/troffrc* is an initialization macro file loaded before any macro packages specified with **-m** options. - */usr/share/groff/1.24.2/tmac/troffrc-end* is an initialization macro file loaded after all macro packages specified with **-m** options. - */usr/share/groff/1.24.2/tmac/*name*.tmac* are macro files distributed with *groff*. - */usr/share/groff/1.24.2/font/dev*name*/DESC* describes the output device *name*. - */usr/share/groff/1.24.2/font/dev*name*/*F describes the font *F* of device *name.* *troffrc* and *troffrc-end* are sought neither in the current nor the home directory by default for security reasons, even if the **-U** option is specified. Use the **-M** command-line option or the *GROFF\_TMAC\_PATH* environment variable to add these directories to the search path if necessary. ## Authors The GNU version of *troff* was originally written by James Clark; he also wrote the original version of this document, which was updated by Werner Lemberg ⟨wl@\\:gnu\\:.org⟩, Bernd Warken ⟨groff\\-bernd\\:.warken\\-72@\\:web\\:.de⟩, and G. Branden Robinson ⟨g.branden\\:.robinson@\\:gmail\\:.com⟩. ## See also *Groff: The GNU Implementation of troff*, by Trent A. Fisher and Werner Lemberg, is the primary *groff* manual. You can browse it interactively with “info groff”. - [*groff*(1)](/groff/1.md) offers an overview of the GNU *roff* system and describes its front end executable. - [*groff*(7)](/groff/7.md) details the *groff* language, including a short but complete reference of all predefined requests, registers, and escape sequences. - [*groff\_char*(7)](/groff_char/7.md) explains the syntax of *groff* special character escape sequences, and lists all special characters predefined by the language. - [*groff\_diff*(7)](/groff_diff/7.md) enumerates the differences between AT&T device-independent *troff* and *groff*. - [*groff\_font*(5)](/groff_font/5.md) covers the format of *groff* device and font description files. - [*groff\_out*(5)](/groff_out/5.md) describes the format of *troff*'s output. - [*groff\_tmac*(5)](/groff_tmac/5.md) includes information about macro files that ship with *groff*. - [*roff*(7)](/roff/7.md) supplies background on *roff* systems in general, including pointers to further related documentation.