1. Executable programs or shell commands
GROFFSection: User Commands (1)
Updated: 23 March 2022
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NAMEgroff - front-end for the groff document formatting system
SYNOPSIS[ -abcegijklpstzCEGNRSUVXZ ] [ -d cs ] [ -D arg ] [ -f fam ] [ -F dir ] [ -I dir ] [ -K arg ] [ -L arg ] [ -m name ] [ -M dir ] [ -n num ] [ -o list ] [ -P arg ] [ -r cn ] [ -T dev ] [ -w name ] [ -W name ] [file ...] -h --help -v [option ...] --version [option ...]
DESCRIPTIONThis document describes the groff program, the main front-end for the groff document formatting system. The groff program and macro suite is the implementation of a roff(7) system within the free software collection GNU The groff system has all features of the classical roff, but adds many extensions.
The groff program allows control of the whole groff system by command-line options. This is a great simplification in comparison to the classical case (which uses pipes only).
OPTIONSThe command line is parsed according to the usual GNU convention. Whitespace is permitted between a command-line option and its argument. Options can be grouped behind a single '-' (minus character). A filename of - (minus character) denotes the standard input.
As groff is a wrapper program for troff both programs share a set of options. But the groff program has some additional, native options and gives a new meaning to some troff options. On the other hand, not all troff options can be fed into groff.
Native groff OptionsThe following options either do not exist for troff or are differently interpreted by groff.
- -D arg
- Set default input encoding used by preconv to arg. Implies -k.
- Preprocess with eqn.
- Preprocess with grn.
- Preprocess with grap. Implies -p.
- --help Print a help message.
- -I dir
- This option may be used to specify a directory to search for files (both those on the command line and those named in .psbb and .so requests, and \X'ps: import' , \X'ps: file' and \X'pdf: pdfpic' escapes). The current directory is always searched first. This option may be specified more than once; the directories are searched in the order specified. No directory search is performed for files specified using an absolute path. This option implies the -s option.
- Preprocess with chem. Implies -p.
- Preprocess with preconv. This is run before any other preprocessor. Please refer to preconv's manual page for its behaviour if no -K (or -D) option is specified.
- -K arg
- Set input encoding used by preconv to arg. Implies -k.
- Send the output to a spooler program for printing. The command that should be used for this is specified by the print command in the device description file, see groff_font(5). If this command is not present, the output is piped into the lpr(1) program by default. See options -L and -X.
- -L arg
- Pass arg to the spooler program. Several arguments should be passed with a separate -L option each. Note that groff does not prepend '-' (a minus sign) to arg before passing it to the spooler program.
- Don't allow newlines within eqn delimiters. This is the same as the -N option in eqn.
- Preprocess with pic.
- -P -option
-P -option -P arg
to the postprocessor.
The option must be specified with the necessary preceding minus
does not prepend any dashes before passing it to the postprocessor.
For example, to pass a title to the
postprocessor, the shell command
- groff -X -P -title -P 'groff it' foo
is equivalent to
- groff -X -Z foo | gxditview -title 'groff it' -
- Preprocess with refer. No mechanism is provided for passing arguments to refer because most refer options have equivalent language elements that can be specified within the document. See refer(1) for more details.
- Preprocess with soelim.
- Safer mode. Pass the -S option to pic and disable the following troff requests: .open, .opena, .pso, .sy, and .pi. For security reasons, safer mode is enabled by default.
- Preprocess with tbl.
- -T dev
Set output device to
For this device,
calls a postprocessor to convert
to its final format.
Real devices in
- TeX DVI format (postprocessor is grodvi).
- xhtml HTML and XHTML output (preprocessors are soelim and pre-grohtml, postprocessor is post-grohtml).
- Canon CAPSL printers (LBP-4 and LBP-8 series laser printers; postprocessor is grolbp).
- HP LaserJet4 compatible (or other PCL5 compatible) printers (postprocessor is grolj4).
- PostScript output (postprocessor is grops).
- Portable Document Format (PDF) output (postprocessor is gropdf).
For the following TTY output devices (postprocessor is always
selects the output encoding:
- 7bit ASCII.
- Latin-1 character set for EBCDIC hosts.
- ISO 8859-1.
- Unicode character set in UTF-8 encoding. This mode has the most useful fonts for TTY mode, so it is the best mode for TTY output.
The following arguments select
as the 'postprocessor' (it is rather a viewing program):
- 75dpi resolution, 10pt document base font.
- 75dpi resolution, 12pt document base font.
- 100dpi resolution, 10pt document base font.
- 100dpi resolution, 12pt document base font.
- The default device is ps.
- Unsafe mode. Reverts to the (old) unsafe behaviour; see option -S.
- --version Output version information of groff and of all programs that are run by it; that is, the given command line is parsed in the usual way, passing -v to all subprograms.
- Output the pipeline that would be run by groff (as a wrapper program) on the standard output, but do not execute it. If given more than once, the commands are both printed on the standard error and run.
instead of using the usual postprocessor to (pre)view a document.
The printing spooler behavior as outlined with options
is carried over to
by determining an argument for the
This sets the default
action and the corresponding menu entry to that value.
only produces good results with
The default resolution for previewing
output is 75dpi; this can be changed by passing the
- groff -X -P-resolution -P100 -man foo.1
- Suppress output generated by troff. Only error messages are printed.
- Do not automatically postprocess groff intermediate output in the usual manner. This will cause the troff output to appear on standard output, replacing the usual postprocessor output; see groff_out(5).
Transparent OptionsThe following options are transparently handed over to the formatter program troff that is called by groff subsequently. These options are described in more detail in troff(1).
- ASCII approximation of output.
- Backtrace on error or warning.
- Disable color output. Please consult the grotty(1) man page for more details.
- Enable compatibility mode.
- -d cs
- -d name=s Define string.
- Disable troff error messages.
- -f fam
- Set default font family.
- -F dir
- Set path for device DESC files.
- Process standard input after the specified input files.
- -m name
- Include macro file name.tmac (or tmac.name); see also groff_tmac(5).
- -M dir
- Path for macro files.
- -n num
- Number the first page num.
- -o list
- Output only pages in list.
- -r cn
- -r name=n Set number register.
- -w name
- Enable warning name. See troff(1) for names.
- -W name
- disable warning name. See troff(1) for names.
USING GROFFThe groff system implements the infrastructure of classical roff; see roff(7) for a survey on how a roff system works in general. Due to the front-end programs available within the groff system, using groff is much easier than classical roff. This section gives an overview of the parts that constitute the groff system. It complements roff(7) with groff-specific features. This section can be regarded as a guide to the documentation around the groff system.
Paper SizeThe virtual paper size used by troff to format the input is controlled globally with the requests .po, .pl, and .ll. See groff_tmac(5) for the 'papersize' macro package which provides a convenient interface.
The physical paper size, giving the actual dimensions of the paper sheets, is controlled by output devices like grops with the command-line options -p and -l. See groff_font(5) and the man pages of the output devices for more details. groff uses the command-line option -P to pass options to output devices; for example, the following selects A4 paper in landscape orientation for the PS device:
- groff -Tps -P-pa4 -P-l ...
Front-endsThe groff program is a wrapper around the troff(1) program. It allows one to specify the preprocessors by command-line options and automatically runs the postprocessor that is appropriate for the selected device. Doing so, the sometimes tedious piping mechanism of classical roff(7) can be avoided.
The grog(1) program can be used for guessing the correct groff command line to format a file.
The groffer(1) program is an all-around viewer for groff files and man pages.
PreprocessorsThe groff preprocessors are reimplementations of the classical preprocessors with moderate extensions. The standard preprocessors distributed with the groff package are
- for mathematical formulae,
- for including gremlin(1) pictures,
- for drawing diagrams,
- for chemical structure diagrams,
- for bibliographic references,
- for including macro files from standard locations,
- for tables.
A new preprocessor not available in classical troff is preconv(1) which converts various input encodings to something groff can understand. It is always run first before any other preprocessor.
Besides these, there are some internal preprocessors that are automatically run with some devices. These aren't visible to the user.
Macro PackagesMacro packages can be included by option -m. The groff system implements and extends all classical macro packages in a compatible way and adds some packages of its own. Actually, the following macro packages come with groff:
- The traditional man page format; see groff_man(7). It can be specified on the command line as -man or -m~man.
- The general package for man pages; it automatically recognizes whether the documents uses the man or the mdoc format and branches to the corresponding macro package. It can be specified on the command line as -mandoc or -m~mandoc.
- The BSD-style man page format; see groff_mdoc(7). It can be specified on the command line as -mdoc or -m~mdoc.
- The classical me document format; see groff_me(7). It can be specified on the command line as -me or -m~me.
- The classical mm document format; see groff_mm(7). It can be specified on the command line as -mm or -m~mm.
- The classical ms document format; see groff_ms(7). It can be specified on the command line as -ms or -m~ms.
- HTML-like macros for inclusion in arbitrary groff documents; see groff_www(7).
Details on the naming of macro files and their placement can be found in groff_tmac(5); this man page also documents some other, minor auxiliary macro packages not mentioned here.
Programming LanguageGeneral concepts common to all roff programming languages are described in roff(7).
The groff extensions to the classical troff language are documented in groff_diff(7).
An overview of language features, including all supported escapes and requests, can be found in groff(7).
FormattersThe central roff formatter within the groff system is troff(1). It provides the features of both the classical troff and nroff, as well as the groff extensions. The command-line option -C switches troff into compatibility mode which tries to emulate classical roff as much as possible.
There is a shell script nroff(1) that emulates the behavior of classical nroff. It tries to automatically select the proper output encoding, according to the current locale.
The formatter program generates intermediate output; see groff_out(7).
DevicesIn roff, the output targets are called devices. A device can be a piece of hardware, e.g., a printer, or a software file format. A device is specified by the option -T. The groff devices are as follows.
- Text output using the ascii(7) character set.
- Text output using the EBCDIC code page IBM cp1047 (e.g., OS/390 Unix).
- TeX DVI format.
- HTML output.
- Text output using the ISO Latin-1 (ISO 8859-1) character set; see iso_8859_1(7).
- Output for Canon CAPSL printers (LBP-4 and LBP-8 series laser printers).
- HP LaserJet4-compatible (or other PCL5-compatible) printers.
- PostScript output; suitable for printers and previewers like gv(1).
- PDF files; suitable for viewing with tools such as evince(1) and okular(1).
- Text output using the Unicode (ISO 10646) character set with UTF-8 encoding; see unicode(7).
- XHTML output.
- 75dpi X Window System output suitable for the previewers xditview(1x) and gxditview(1). A variant for a 12pt document base font is X75-12.
- 100dpi X Window System output suitable for the previewers xditview(1x) and gxditview(1). A variant for a 12pt document base font is X100-12.
The postprocessor to be used for a device is specified by the postpro command in the device description file; see groff_font(5). This can be overridden with the -X option.
Postprocessorsgroff provides 3~hardware postprocessors:
- for some Canon printers,
- for printers compatible to the HP LaserJet~4 and PCL5,
- for text output using various encodings, e.g., on text-oriented terminals or line printers.
Today, most printing or drawing hardware is handled by the operating system, by device drivers, or by software interfaces, usually accepting PostScript. Consequently, there isn't an urgent need for more hardware device postprocessors.
The groff software devices for conversion into other document file formats are
- for the DVI format,
- for HTML and XHTML formats,
- for PostScript.
- for PDF.
Combined with the many existing free conversion tools this should be sufficient to convert a troff document into virtually any existing data format.
UtilitiesThe following utility programs around groff are available.
- Add information to troff font description files for use with groff.
- Create font description files for PostScript device.
- Convert an eqn image into a cropped image.
- Mark differences between groff, nroff, or troff files.
- Convert a grap diagram into a cropped bitmap image.
- General viewer program for groff files and man pages.
- The groff X viewer, the GNU version of xditview.
- Create font description files for lj4 device.
- Make inverted index for bibliographic databases.
- Search bibliographic databases.
- Interactively search bibliographic databases.
- Create PDF documents using groff.
- Translate a PostScript font in .pfb format to ASCII.
- Convert a pic diagram into a cropped image.
- Create font description files for TeX DVI device.
- roff viewer historically distributed with the X Window System.
- Convert X font metrics into GNU troff font metrics.
ENVIRONMENTNormally, the path separator in the following environment variables is the colon; this may vary depending on the operating system. For example, DOS and Windows use a semicolon instead.
- This search path, followed by PATH, is used for commands that are executed by groff. If it is not set then the directory where the groff binaries were installed is prepended to PATH.
- When there is a need to run different roff implementations at the same time groff provides the facility to prepend a prefix to most of its programs that could provoke name clashings at run time (default is to have none). Historically, this prefix was the character g, but it can be anything. For example, gtroff stood for groff's troff, gtbl for the groff version of tbl. By setting GROFF_COMMAND_PREFIX to different values, the different roff installations can be addressed. More exactly, if it is set to prefix xxx then groff as a wrapper program internally calls xxxtroff instead of troff. This also applies to the preprocessors eqn, grn, pic, refer, tbl, soelim, and to the utilities indxbib and lookbib. This feature does not apply to any programs different from the ones above (most notably groff itself) since they are unique to the groff package.
- The value of this environment value is passed to the preconv preprocessor to select the encoding of input files. Setting this option implies groff's command-line option -k (this is, groff actually always calls preconv). If set without a value, groff calls preconv without arguments. An explicit -K command-line option overrides the value of GROFF_ENCODING. See preconv(1) for details.
- A list of directories in which to search for the devname directory in addition to the default ones. See troff(1) and groff_font(5) for more details.
- A list of directories in which to search for macro files in addition to the default directories. See troff(1) and groff_tmac(5) for more details.
- The directory in which temporary files are created. If this is not set but the environment variable TMPDIR instead, temporary files are created in the directory TMPDIR. On MS-DOS and Windows platforms, the environment variables TMP and TEMP (in that order) are searched also, after GROFF_TMPDIR and TMPDIR. Otherwise, temporary files are created in /tmp. The refer(1), groffer(1), grohtml(1), and grops(1) commands use temporary files.
- Preset the default device. If this is not set the ps device is used as default. This device name is overwritten by the option -T.
EXAMPLESThe following example illustrates the power of the groff program as a wrapper around troff.
To process a roff file using the preprocessors tbl and pic and the me macro set, classical troff had to be called by
- pic foo.me | tbl | troff -me -Tlatin1 | grotty
Using groff, this pipe can be shortened to the equivalent command
- groff -p -t -me -T latin1 foo.me
An even easier way to call this is to use grog(1) to guess the preprocessor and macro options and execute the generated command (by using backquotes to specify shell command substitution)
- `grog -Tlatin1 foo.me`
The simplest way is to view the contents in an automated way by calling
- groffer foo.me
BUGSOn EBCDIC hosts (e.g., OS/390 Unix), output devices ascii and latin1 aren't available. Similarly, output for EBCDIC code page cp1047 is not available on ASCII based operating systems.
INSTALLATION DIRECTORIESgroff installs files in varying locations depending on its compile-time configuration. On this installation, the following locations are used.
- Application defaults directory for gxditview(1).
- Directory containing groff's executable commands.
- List of common words for indxbib(1).
- Directory for data files.
- Default index for lkbib(1) and refer(1).
- Documentation directory.
- Example directory.
- Font directory.
- HTML documentation directory.
- Legacy font directory.
- Local font directory.
- Local macro package (tmac file) directory.
- Macro package (tmac file) directory.
- Font directory for compatibility with old versions of groff; see grops(1).
- PDF documentation directory.
- System macro package (tmac file) directory.
groff Macro DirectoryThis contains all information related to macro packages. Note that more than a single directory is searched for those files as documented in groff_tmac(5). For the groff installation corresponding to this document, it is located at /usr/share/groff/1.22.4/tmac. The following files contained in the groff macro directory have a special meaning:
- Initialization file for troff. This is interpreted by troff before reading the macro sets and any input.
- Final startup file for troff. It is parsed after all macro sets have been read.
- tmac.name Macro file for macro package name.
groff Font DirectoryThis contains all information related to output devices. Note that more than a single directory is searched for those files; see troff(1). For the groff installation corresponding to this document, it is located at /usr/share/groff/1.22.4/font. The following files contained in the groff font directory have a special meaning:
- Device description file for device name, see groff_font(5).
- Font file for font F of device name.
AVAILABILITYInformation on how to get groff and related information is available at the groff page of the GNU website
Three groff mailing lists are available:
- bug tracker activity (read-only)
- general discussion and
- commit activity (read-only) which reports changes to groff's source code repository by its developers.
Details on repository access and much more can be found in the file README at the top directory of the groff source package.
A free implementation of the grap preprocessor, written by Ted Faber can be found at the grap website This is the only grap supported by groff.
AUTHORSgroff was written by James Clark This document was rewritten, enhanced, and put under the FDL license in 2002 by Bernd Warken
SEE ALSOGroff: 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".
Due to its complex structure, the groff system has many man pages. They can be read with man(1) or groffer(1).
But there are special sections of man pages. groff has man pages in sections 1, 5,and 7. When there are several man pages with the same name in the same man section, the one with the lowest section is should as first. The other man pages can be shown anyway by adding the section number as argument before the man page name. Reading the man page about the groff language is done by one of
man 7 groff groffer 7 groff
- Introduction, history and further readings:
- Viewer for groff files:
- groffer(1), gxditview(1), xditview(1x).
- Wrapper programs for formatters:
- groff(1), grog(1).
- Roff preprocessors:
- eqn(1), grn(1), pic(1), chem(1), preconv(1), refer(1), soelim(1), tbl(1), grap(1).
- Roff language with the groff extensions:
- groff(7), groff_char(7), groff_diff(7), groff_font(5).
- Roff formatter programs:
- nroff(1), troff(1), ditroff(7).
- The intermediate output language:
- Postprocessors for the output devices:
- grodvi(1), grohtml(1), grolbp(1), grolj4(1), lj4_font(5), grops(1), gropdf(1), grotty(1).
- Groff macro packages and macro-specific utilities:
- groff_tmac(5), groff_man(7), groff_mdoc(7), groff_me(7), groff_mm(7), groff_mmse(7) (only in Swedish locales), groff_mom(7), groff_ms(7), groff_www(7), groff_trace(7), mmroff(7).
- The following utilities are available:
- USING GROFF
- INSTALLATION DIRECTORIES
- SEE ALSO
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