Provided by: manpages-pt_20040726-5_all 
NAME
mdoc.samples — tutorial sampler for writing BSD manuals with -mdoc
SYNOPSIS
man mdoc.samples
DESCRIPTION
A tutorial sampler for writing BSD manual pages with the -mdoc macro package, a content-based and
domain-based formatting package for troff(1). Its predecessor, the -man(7) package, addressed page
layout leaving the manipulation of fonts and other typesetting details to the individual author. In
-mdoc, page layout macros make up the page structure domain which consists of macros for titles, section
headers, displays and lists. Essentially items which affect the physical position of text on a formatted
page. In addition to the page structure domain, there are two more domains, the manual domain and the
general text domain. The general text domain is defined as macros which perform tasks such as quoting or
emphasizing pieces of text. The manual domain is defined as macros that are a subset of the day to day
informal language used to describe commands, routines and related BSD files. Macros in the manual domain
handle command names, command line arguments and options, function names, function parameters, pathnames,
variables, cross references to other manual pages, and so on. These domain items have value for both the
author and the future user of the manual page. It is hoped the consistency gained across the manual set
will provide easier translation to future documentation tools.
Throughout the Unix manual pages, a manual entry is simply referred to as a man page, regardless of
actual length and without sexist intention.
GETTING STARTED
Since a tutorial document is normally read when a person desires to use the material immediately, the
assumption has been made that the user of this document may be impatient. The material presented in the
remained of this document is outlined as follows:
1. TROFF IDIOSYNCRASIES
Macro Usage.
Passing Space Characters in an Argument.
Trailing Blank Space Characters (a warning).
Escaping Special Characters.
2. THE ANATOMY OF A MAN PAGE
A manual page template.
3. TITLE MACROS.
4. INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS.
What's in a name....
General Syntax.
5. MANUAL DOMAIN
Addresses.
Author name.
Arguments.
Configuration Declarations (section four only).
Command Modifier.
Defined Variables.
Errno's (Section two only).
Environment Variables.
Function Argument.
Function Declaration.
Flags.
Functions (library routines).
Function Types.
Interactive Commands.
Names.
Options.
Pathnames.
Variables.
Cross References.
6. GENERAL TEXT DOMAIN
AT&T Macro.
BSD Macro.
FreeBSD Macro.
UNIX Macro.
Enclosure/Quoting Macros
Angle Bracket Quote/Enclosure.
Bracket Quotes/Enclosure.
Double Quote macro/Enclosure.
Parenthesis Quote/Enclosure.
Single Quotes/Enclosure.
Prefix Macro.
No-Op or Normal Text Macro.
No Space Macro.
Section Cross References.
References and Citations.
Return Values (sections two and three only)
Trade Names (Acronyms and Type Names).
Extended Arguments.
7. PAGE STRUCTURE DOMAIN
Section Headers.
Paragraphs and Line Spacing.
Keeps.
Displays.
Font Modes (Emphasis, Literal, and Symbolic).
Lists and Columns.
8. PREDEFINED STRINGS
9. DIAGNOSTICS
10. FORMATTING WITH GROFF, TROFF AND NROFF
11. BUGS
TROFF IDIOSYNCRASIES
The -mdoc package attempts to simplify the process of writing a man page. Theoretically, one should not
have to learn the dirty details of troff(1) to use -mdoc; however, there are a few limitations which are
unavoidable and best gotten out of the way. And, too, be forewarned, this package is not fast.
Macro Usage
As in troff(1), a macro is called by placing a ‘.’ (dot character) at the beginning of a line followed by
the two character name for the macro. Arguments may follow the macro separated by spaces. It is the dot
character at the beginning of the line which causes troff(1) to interpret the next two characters as a
macro name. To place a ‘.’ (dot character) at the beginning of a line in some context other than a macro
invocation, precede the ‘.’ (dot) with the ‘\&’ escape sequence. The ‘\&’ translates literally to a zero
width space, and is never displayed in the output.
In general, troff(1) macros accept up to nine arguments, any extra arguments are ignored. Most macros in
-mdoc accept nine arguments and, in limited cases, arguments may be continued or extended on the next
line (See “Extensions”). A few macros handle quoted arguments (see “Passing Space Characters in an
Argument” below).
Most of the -mdoc general text domain and manual domain macros are special in that their argument lists
are parsed for callable macro names. This means an argument on the argument list which matches a general
text or manual domain macro name and is determined to be callable will be executed or called when it is
processed. In this case the argument, although the name of a macro, is not preceded by a ‘.’ (dot). It
is in this manner that many macros are nested; for example the option macro, ‘.Op’, may call the flag and
argument macros, ‘Fl’ and ‘Ar’, to specify an optional flag with an argument:
[-s bytes] is produced by .Op Fl s Ar bytes
To prevent a two character string from being interpreted as a macro name, precede the string with the
escape sequence ‘\&’:
[Fl s Ar bytes] is produced by .Op \&Fl s \&Ar bytes
Here the strings ‘Fl’ and ‘Ar’ are not interpreted as macros. Macros whose argument lists are parsed for
callable arguments are referred to as parsed and macros which may be called from an argument list are
referred to as callable throughout this document and in the companion quick reference manual mdoc(7).
This is a technical faux pas as almost all of the macros in -mdoc are parsed, but as it was cumbersome to
constantly refer to macros as being callable and being able to call other macros, the term parsed has
been used.
Passing Space Characters in an Argument
Sometimes it is desirable to give as one argument a string containing one or more blank space characters.
This may be necessary to defeat the nine argument limit or to specify arguments to macros which expect
particular arrangement of items in the argument list. For example, the function macro ‘.Fn’ expects the
first argument to be the name of a function and any remaining arguments to be function parameters. As
ANSI C stipulates the declaration of function parameters in the parenthesized parameter list, each
parameter is guaranteed to be at minimum a two word string. For example, int foo.
There are two possible ways to pass an argument which contains an embedded space. Implementation note:
Unfortunately, the most convenient way of passing spaces in between quotes by reassigning individual
arguments before parsing was fairly expensive speed wise and space wise to implement in all the macros
for AT&T troff. It is not expensive for groff but for the sake of portability, has been limited to the
following macros which need it the most:
Cd Configuration declaration (section 4 “SYNOPSIS”)
Bl Begin list (for the width specifier).
Em Emphasized text.
Fn Functions (sections two and four).
It List items.
Li Literal text.
Sy Symbolic text.
%B Book titles.
%J Journal names.
%O Optional notes for a reference.
%R Report title (in a reference).
%T Title of article in a book or journal.
One way of passing a string containing blank spaces is to use the hard or unpaddable space character
‘\ ’, that is, a blank space preceded by the escape character ‘\’. This method may be used with any
macro but has the side effect of interfering with the adjustment of text over the length of a line.
Troff sees the hard space as if it were any other printable character and cannot split the string into
blank or newline separated pieces as one would expect. The method is useful for strings which are not
expected to overlap a line boundary. For example:
fetch(char *str) is created by ‘.Fn fetch char\ *str’
fetch(char *str) can also be created by ‘.Fn fetch "char *str"’
If the ‘\’ or quotes were omitted, ‘.Fn’ would see three arguments and the result would be:
fetch(char, *str)
For an example of what happens when the parameter list overlaps a newline boundary, see the “BUGS”
section.
Trailing Blank Space Characters
Troff can be confused by blank space characters at the end of a line. It is a wise preventive measure to
globally remove all blank spaces from <blank-space><end-of-line> character sequences. Should the need
arise to force a blank character at the end of a line, it may be forced with an unpaddable space and the
‘\&’ escape character. For example, ‘string\ \&’.
Escaping Special Characters
Special characters like the newline character ‘\n’, are handled by replacing the ‘\’ with ‘\e’ (e.g.
‘\en’) to preserve the backslash.
THE ANATOMY OF A MAN PAGE
The body of a man page is easily constructed from a basic template found in the file
/usr/share/misc/mdoc.template. Several example man pages can also be found in /usr/share/examples/mdoc.
A manual page template
.\" The following requests are required for all man pages.
.Dd Month day, year
.Os OPERATING_SYSTEM [version/release]
.Dt DOCUMENT_TITLE [section number] [volume]
.Sh NAME
.Nm name
.Nd one line description of name
.Sh SYNOPSIS
.Sh DESCRIPTION
.\" The following requests should be uncommented and
.\" used where appropriate. This next request is
.\" for sections 2 and 3 function return values only.
.\" .Sh RETURN VALUES
.\" This next request is for sections 1, 6, 7 & 8 only
.\" .Sh ENVIRONMENT
.\" .Sh FILES
.\" .Sh EXAMPLES
.\" This next request is for sections 1, 6, 7 & 8 only
.\" (command return values (to shell) and
.\" fprintf/stderr type diagnostics)
.\" .Sh DIAGNOSTICS
.\" The next request is for sections 2 and 3 error
.\" and signal handling only.
.\" .Sh ERRORS
.\" .Sh SEE ALSO
.\" .Sh STANDARDS
.\" .Sh HISTORY
.\" .Sh AUTHORS
.\" .Sh BUGS
The first items in the template are the macros (.Dd, .Os, .Dt); the document date, the operating system
the man page or subject source is developed or modified for, and the man page title (in upper case) along
with the section of the manual the page belongs in. These macros identify the page, and are discussed
below in “TITLE MACROS”.
The remaining items in the template are section headers (.Sh); of which “NAME”, “SYNOPSIS” and
“DESCRIPTION” are mandatory. The headers are discussed in “PAGE STRUCTURE DOMAIN”, after presentation of
“MANUAL DOMAIN”. Several content macros are used to demonstrate page layout macros; reading about
content macros before page layout macros is recommended.
TITLE MACROS
The title macros are the first portion of the page structure domain, but are presented first and separate
for someone who wishes to start writing a man page yesterday. Three header macros designate the document
title or manual page title, the operating system, and the date of authorship. These macros are one
called once at the very beginning of the document and are used to construct the headers and footers only.
.Dt DOCUMENT_TITLE section# [volume]
The document title is the subject of the man page and must be in CAPITALS due to troff
limitations. The section number may be 1, ..., 8, and if it is specified, the volume title may
be omitted. A volume title may be arbitrary or one of the following:
AMD UNIX Ancestral Manual Documents
SMM UNIX System Manager's Manual
URM UNIX Reference Manual
PRM UNIX Programmer's Manual
The default volume labeling is URM for sections 1, 6, and 7; SMM for section 8; PRM for sections
2, 3, 4, and 5.
.Os operating_system release#
The name of the operating system should be the common acronym, e.g. BSD or FreeBSD or ATT. The
release should be the standard release nomenclature for the system specified, e.g. 4.3,
4.3+Tahoe, V.3, V.4. Unrecognized arguments are displayed as given in the page footer. For
instance, a typical footer might be:
.Os BSD 4.3
or
.Os FreeBSD 2.2
or for a locally produced set
.Os CS Department
The Berkeley default, ‘.Os’ without an argument, has been defined as BSD in the site specific
file /usr/share/tmac/mdoc/doc-common. It really should default to LOCAL. Note, if the ‘.Os’
macro is not present, the bottom left corner of the page will be ugly.
.Dd month day, year
The date should be written formally:
January 25, 1989
INTRODUCTION OF MANUAL AND GENERAL TEXT DOMAINS
What's in a name...
The manual domain macro names are derived from the day to day informal language used to describe
commands, subroutines and related files. Slightly different variations of this language are used to
describe the three different aspects of writing a man page. First, there is the description of -mdoc
macro request usage. Second is the description of a Unix command with -mdoc macros and third, the
description of a command to a user in the verbal sense; that is, discussion of a command in the text of a
man page.
In the first case, troff(1) macros are themselves a type of command; the general syntax for a troff
command is:
.Va argument1 argument2 ... argument9
The ‘.Va’ is a macro command or request, and anything following it is an argument to be processed. In
the second case, the description of a Unix command using the content macros is a bit more involved; a
typical “SYNOPSIS” command line might be displayed as:
filter [-flag] infile outfile
Here, filter is the command name and the bracketed string -flag is a flag argument designated as optional
by the option brackets. In -mdoc terms, infile and outfile are called arguments. The macros which
formatted the above example:
.Nm filter
.Op Fl flag
.Ar infile outfile
In the third case, discussion of commands and command syntax includes both examples above, but may add
more detail. The arguments infile and outfile from the example above might be referred to as operands or
file arguments. Some command line argument lists are quite long:
make [-eiknqrstv] [-D variable] [-d flags] [-f makefile] [-I directory] [-j max_jobs]
[variable=value] [target ...]
Here one might talk about the command make and qualify the argument makefile, as an argument to the flag,
-f, or discuss the optional file operand target. In the verbal context, such detail can prevent
confusion, however the -mdoc package does not have a macro for an argument to a flag. Instead the ‘Ar’
argument macro is used for an operand or file argument like target as well as an argument to a flag like
variable. The make command line was produced from:
.Nm make
.Op Fl eiknqrstv
.Op Fl D Ar variable
.Op Fl d Ar flags
.Op Fl f Ar makefile
.Op Fl I Ar directory
.Op Fl j Ar max_jobs
.Op Ar variable=value
.Bk -words
.Op Ar target ...
.Ek
The ‘.Bk’ and ‘.Ek’ macros are explained in “Keeps”.
General Syntax
The manual domain and general text domain macros share a similar syntax with a few minor deviations:
‘.Ar’, ‘.Fl’, ‘.Nm’, and ‘.Pa’ differ only when called without arguments; ‘.Fn’ and ‘.Xr’ impose an order
on their argument lists and the ‘.Op’ and ‘.Fn’ macros have nesting limitations. All content macros are
capable of recognizing and properly handling punctuation, provided each punctuation character is
separated by a leading space. If an request is given:
.Li sptr, ptr),
The result is:
sptr, ptr),
The punctuation is not recognized and all is output in the literal font. If the punctuation is separated
by a leading white space:
.Li sptr , ptr ) ,
The result is:
sptr, ptr),
The punctuation is now recognized and is output in the default font distinguishing it from the strings in
literal font.
To remove the special meaning from a punctuation character escape it with ‘\&’. Troff is limited as a
macro language, and has difficulty when presented with a string containing a member of the mathematical,
logical or quotation set:
{+,-,/,*,%,<,>,<=,>=,=,==,&,`,',"}
The problem is that troff may assume it is supposed to actually perform the operation or evaluation
suggested by the characters. To prevent the accidental evaluation of these characters, escape them with
‘\&’. Typical syntax is shown in the first content macro displayed below, ‘.Ad’.
MANUAL DOMAIN
Address Macro
The address macro identifies an address construct of the form addr1[,addr2[,addr3]].
Usage: .Ad address ...
.Ad addr1 addr1
.Ad addr1 . addr1.
.Ad addr1 , file2
addr1, file2
.Ad f1 , f2 , f3 :
f1, f2, f3:
.Ad addr ) ) ,
addr)),
It is an error to call ‘.Ad’ without arguments. ‘.Ad’ is callable by other macros and is parsed.
Author Name
The ‘.An’ macro is used to specify the name of the author of the item being documented, or the name of
the author of the actual manual page. Any remaining arguments after the name information are assumed to
be punctuation.
Usage: .An author_name
.An Joe Author
Joe Author
.An Joe Author ,
Joe Author,
.An Joe Author Aq nobody@FreeBSD.ORG
Joe Author <nobody@FreeBSD.ORG>
.An Joe Author ) ) ,
Joe Author)),
The ‘.An’ macro is parsed and is callable. It is an error to call ‘.An’ without any arguments.
Argument Macro
The ‘.Ar’ argument macro may be used whenever a command line argument is referenced.
Usage: .Ar argument ...
.Ar file ...
.Ar file1 file1
.Ar file1 . file1.
.Ar file1 file2
file1 file2
.Ar f1 f2 f3 :
f1 f2 f3:
.Ar file ) ) ,
file)),
If ‘.Ar’ is called without arguments ‘file ...’ is assumed. The ‘.Ar’ macro is parsed and is callable.
Configuration Declaration (section four only)
The ‘.Cd’ macro is used to demonstrate a config(8) declaration for a device interface in a section four
manual. This macro accepts quoted arguments (double quotes only).
device le0 at scode? produced by: ‘.Cd device le0 at scode?’.
Command Modifier
The command modifier is identical to the ‘.Fl’ (flag) command with the exception the ‘.Cm’ macro does not
assert a dash in front of every argument. Traditionally flags are marked by the preceding dash, some
commands or subsets of commands do not use them. Command modifiers may also be specified in conjunction
with interactive commands such as editor commands. See “Flags”.
Defined Variables
A variable which is defined in an include file is specified by the macro ‘.Dv’.
Usage: .Dv defined_variable ...
.Dv MAXHOSTNAMELEN
MAXHOSTNAMELEN
.Dv TIOCGPGRP )
TIOCGPGRP)
It is an error to call ‘.Dv’ without arguments. ‘.Dv’ is parsed and is callable.
Errno's (Section two only)
The ‘.Er’ errno macro specifies the error return value for section two library routines. The second
example below shows ‘.Er’ used with the ‘.Bq’ general text domain macro, as it would be used in a section
two manual page.
Usage: .Er ERRNOTYPE ...
.Er ENOENT
ENOENT
.Er ENOENT ) ;
ENOENT);
.Bq Er ENOTDIR
[ENOTDIR]
It is an error to call ‘.Er’ without arguments. The ‘.Er’ macro is parsed and is callable.
Environment Variables
The ‘.Ev’ macro specifies an environment variable.
Usage: .Ev argument ...
.Ev DISPLAY
DISPLAY
.Ev PATH . PATH.
.Ev PRINTER ) ) ,
PRINTER)),
It is an error to call ‘.Ev’ without arguments. The ‘.Ev’ macro is parsed and is callable.
Function Argument
The ‘.Fa’ macro is used to refer to function arguments (parameters) outside of the “SYNOPSIS” section of
the manual or inside the “SYNOPSIS” section should a parameter list be too long for the ‘.Fn’ macro and
the enclosure macros ‘.Fo’ and ‘.Fc’ must be used. ‘.Fa’ may also be used to refer to structure members.
Usage: .Fa function_argument ...
.Fa d_namlen ) ) ,
d_namlen)),
.Fa iov_len iov_len
It is an error to call ‘.Fa’ without arguments. ‘.Fa’ is parsed and is callable.
Function Declaration
The ‘.Fd’ macro is used in the “SYNOPSIS” section with section two or three functions. The ‘.Fd’ macro
does not call other macros and is not callable by other macros.
Usage: .Fd include_file (or defined variable)
In the “SYNOPSIS” section a ‘.Fd’ request causes a line break if a function has already been presented
and a break has not occurred. This leaves a nice vertical space in between the previous function call
and the declaration for the next function.
Flags
The ‘.Fl’ macro handles command line flags. It prepends a dash, ‘-’, to the flag. For interactive
command flags, which are not prepended with a dash, the ‘.Cm’ (command modifier) macro is identical, but
without the dash.
Usage: .Fl argument ...
.Fl -
.Fl cfv -cfv
.Fl cfv . -cfv.
.Fl s v t -s -v -t
.Fl - , --,
.Fl xyz ) , -xyz),
The ‘.Fl’ macro without any arguments results in a dash representing stdin/stdout. Note that giving
‘.Fl’ a single dash, will result in two dashes. The ‘.Fl’ macro is parsed and is callable.
Functions (library routines)
The .Fn macro is modeled on ANSI C conventions.
Usage: .Fn [type] function [[type] parameters ... ]
.Fn getchar getchar()
.Fn strlen ) , strlen()),
.Fn "int align" "const * char *sptrs", int align(const * char *sptrs),
It is an error to call ‘.Fn’ without any arguments. The ‘.Fn’ macro is parsed and is callable, note that
any call to another macro signals the end of the ‘.Fn’ call (it will close-parenthesis at that point).
For functions that have more than eight parameters (and this is rare), the macros ‘.Fo’ (function open)
and ‘.Fc’ (function close) may be used with ‘.Fa’ (function argument) to get around the limitation. For
example:
.Fo "int res_mkquery"
.Fa "int op"
.Fa "char *dname"
.Fa "int class"
.Fa "int type"
.Fa "char *data"
.Fa "int datalen"
.Fa "struct rrec *newrr"
.Fa "char *buf"
.Fa "int buflen"
.Fc
Produces:
int res_mkquery(int op, char *dname, int class, int type, char *data, int datalen,
struct rrec *newrr, char *buf, int buflen)
The ‘.Fo’ and ‘.Fc’ macros are parsed and are callable. In the “SYNOPSIS” section, the function will
always begin at the beginning of line. If there is more than one function presented in the “SYNOPSIS”
section and a function type has not been given, a line break will occur, leaving a nice vertical space
between the current function name and the one prior. At the moment, ‘.Fn’ does not check its word
boundaries against troff line lengths and may split across a newline ungracefully. This will be fixed in
the near future.
Function Type
This macro is intended for the “SYNOPSIS” section. It may be used anywhere else in the man page without
problems, but its main purpose is to present the function type in kernel normal form for the “SYNOPSIS”
of sections two and three (it causes a line break allowing the function name to appear on the next line).
Usage: .Ft type ...
.Ft struct stat struct stat
The ‘.Ft’ request is not callable by other macros.
Interactive Commands
The ‘.Ic’ macro designates an interactive or internal command.
Usage: .Ic argument ...
.Ic :wq :wq
.Ic do while {...} do while {...}
.Ic setenv , unsetenv
setenv, unsetenv
It is an error to call ‘.Ic’ without arguments. The ‘.Ic’ macro is parsed and is callable.
Name Macro
The ‘.Nm’ macro is used for the document title or subject name. It has the peculiarity of remembering
the first argument it was called with, which should always be the subject name of the page. When called
without arguments, ‘.Nm’ regurgitates this initial name for the sole purpose of making less work for the
author. Note: a section two or three document function name is addressed with the ‘.Nm’ in the “NAME”
section, and with ‘.Fn’ in the “SYNOPSIS” and remaining sections. For interactive commands, such as the
‘while’ command keyword in csh(1), the ‘.Ic’ macro should be used. While the ‘.Ic’ is nearly identical
to ‘.Nm’, it can not recall the first argument it was invoked with.
Usage: .Nm argument ...
.Nm mdoc.sample
mdoc.sample
.Nm \-mdoc -mdoc.
.Nm foo ) ) ,
foo)),
.Nm mdoc.samples
The ‘.Nm’ macro is parsed and is callable.
Options
The ‘.Op’ macro places option brackets around the any remaining arguments on the command line, and places
any trailing punctuation outside the brackets. The macros ‘.Oc’ and ‘.Oo’ may be used across one or more
lines.
Usage: .Op options ...
.Op []
.Op Fl k [-k]
.Op Fl k ) . [-k]).
.Op Fl k Ar kookfile [-k kookfile]
.Op Fl k Ar kookfile ,
[-k kookfile],
.Op Ar objfil Op Ar corfil
[objfil [corfil]]
.Op Fl c Ar objfil Op Ar corfil ,
[-c objfil [corfil]],
.Op word1 word2 [word1 word2]
The ‘.Oc’ and ‘.Oo’ macros:
.Oo
.Op Fl k Ar kilobytes
.Op Fl i Ar interval
.Op Fl c Ar count
.Oc
Produce: [[-k kilobytes] [-i interval] [-c count]]
The macros ‘.Op’, ‘.Oc’ and ‘.Oo’ are parsed and are callable.
Pathnames
The ‘.Pa’ macro formats path or file names.
Usage: .Pa pathname
.Pa /usr/share /usr/share
.Pa /tmp/fooXXXXX ) .
/tmp/fooXXXXX).
The ‘.Pa’ macro is parsed and is callable.
Variables
Generic variable reference:
Usage: .Va variable ...
.Va count count
.Va settimer,
settimer,
.Va int *prt ) :
int *prt):
.Va char s ] ) ) ,
char s])),
It is an error to call ‘.Va’ without any arguments. The ‘.Va’ macro is parsed and is callable.
Manual Page Cross References
The ‘.Xr’ macro expects the first argument to be a manual page name, and the second argument, if it
exists, to be either a section page number or punctuation. Any remaining arguments are assumed to be
punctuation.
Usage: .Xr man_page [1,...,8]
.Xr mdoc mdoc
.Xr mdoc , mdoc,
.Xr mdoc 7 mdoc(7)
.Xr mdoc 7 ) ) ,
mdoc(7))),
The ‘.Xr’ macro is parsed and is callable. It is an error to call ‘.Xr’ without any arguments.
GENERAL TEXT DOMAIN
AT&T Macro
Usage: .At [v6 | v7 | 32v | V.1 | V.4] ...
.At AT&T UNIX
.At v6 . Version 6 AT&T UNIX.
The ‘.At’ macro is not parsed and not callable. It accepts at most two arguments.
BSD Macro
Usage: .Bx [Version/release] ...
.Bx BSD
.Bx 4.3 .
4.3BSD.
The ‘.Bx’ macro is parsed and is callable.
FreeBSD Macro
Usage: .Fx Version.release ...
.Fx 2.2 . FreeBSD 2.2.
The ‘.Fx’ macro is not parsed and not callable. It accepts at most two arguments.
UNIX Macro
Usage: .Ux ...
.Ux Unix
The ‘.Ux’ macro is parsed and is callable.
Enclosure and Quoting Macros
The concept of enclosure is similar to quoting. The object being to enclose one or more strings between
a pair of characters like quotes or parentheses. The terms quoting and enclosure are used
interchangeably throughout this document. Most of the one line enclosure macros end in small letter ‘q’
to give a hint of quoting, but there are a few irregularities. For each enclosure macro there is also a
pair of open and close macros which end in small letters ‘o’ and ‘c’ respectively. These can be used
across one or more lines of text and while they have nesting limitations, the one line quote macros can
be used inside of them.
Quote Close Open Function Result
.Aq .Ac .Ao Angle Bracket Enclosure <string>
.Bq .Bc .Bo Bracket Enclosure [string]
.Dq .Dc .Do Double Quote ``string''
.Ec .Eo Enclose String (in XX) XXstringXX
.Pq .Pc .Po Parenthesis Enclosure (string)
.Ql Quoted Literal `st' or string
.Qq .Qc .Qo Straight Double Quote "string"
.Sq .Sc .So Single Quote `string'
Except for the irregular macros noted below, all of the quoting macros are parsed and callable. All
handle punctuation properly, as long as it is presented one character at a time and separated by spaces.
The quoting macros examine opening and closing punctuation to determine whether it comes before or after
the enclosing string. This makes some nesting possible.
.Ec, .Eo These macros expect the first argument to be the opening and closing strings respectively.
.Ql The quoted literal macro behaves differently for troff than nroff. If formatted with nroff, a
quoted literal is always quoted. If formatted with troff, an item is only quoted if the width
of the item is less than three constant width characters. This is to make short strings more
visible where the font change to literal (constant width) is less noticeable.
.Pf The prefix macro is not callable, but it is parsed:
.Pf ( Fa name2
becomes (name2.
The ‘.Ns’ (no space) macro performs the analogous suffix function.
Examples of quoting:
.Aq ⟨⟩
.Aq Ar ctype.h ) , ⟨ctype.h⟩),
.Bq []
.Bq Em Greek , French .
[Greek, French].
.Dq “”
.Dq string abc . “string abc”.
.Dq ´^[A-Z]´ “´^[A-Z]´”
.Ql man mdoc ‘man mdoc’
.Qq ""
.Qq string ) , "string"),
.Qq string Ns ), "string),"
.Sq ‘’
.Sq string ‘string’
For a good example of nested enclosure macros, see the ‘.Op’ option macro. It was created from the same
underlying enclosure macros as those presented in the list above. The ‘.Xo’ and ‘.Xc’ extended argument
list macros were also built from the same underlying routines and are a good example of -mdoc macro usage
at its worst.
No-Op or Normal Text Macro
The macro ‘.No’ is a hack for words in a macro command line which should not be formatted and follows the
conventional syntax for content macros.
Space Macro
The ‘.Ns’ macro eliminates unwanted spaces in between macro requests. It is useful for old style
argument lists where there is no space between the flag and argument:
.Op Fl I Ns Ar directory
produces [-Idirectory]
Note: the ‘.Ns’ macro always invokes the ‘.No’ macro after eliminating the space unless another macro
name follows it. The macro ‘.Ns’ is parsed and is callable.
Section Cross References
The ‘.Sx’ macro designates a reference to a section header within the same document. It is parsed and is
callable.
.Sx FILES “FILES”
References and Citations
The following macros make a modest attempt to handle references. At best, the macros make it convenient
to manually drop in a subset of refer style references.
.Rs Reference Start. Causes a line break and begins collection of reference information until
the reference end macro is read.
.Re Reference End. The reference is printed.
.%A Reference author name, one name per invocation.
.%B Book title.
.%C City/place.
.%D Date.
.%J Journal name.
.%N Issue number.
.%O Optional information.
.%P Page number.
.%R Report name.
.%T Title of article.
.%V Volume(s).
The macros beginning with ‘%’ are not callable, and are parsed only for the trade name macro which
returns to its caller. (And not very predictably at the moment either.) The purpose is to allow trade
names to be pretty printed in troff/ditroff output.
Return Values
The ‘.Rv’ macro generates text for use in the “RETURN VALUES” section.
Usage: .Rv [-std function]
‘.Rv -std atexit’ will generate the following text:
The atexit() function returns the value 0 if successful; otherwise the value -1 is returned and the
global variable errno is set to indicate the error.
The -std option is valid only for manual page sections 2 and 3.
Trade Names (or Acronyms and Type Names)
The trade name macro is generally a small caps macro for all upper case words longer than two characters.
Usage: .Tn symbol ...
.Tn DEC
DEC
.Tn ASCII
ASCII
The ‘.Tn’ macro is parsed and is callable by other macros.
Extended Arguments
The ‘.Xo’ and ‘.Xc’ macros allow one to extend an argument list on a macro boundary. Argument lists
cannot be extended within a macro which expects all of its arguments on one line such as ‘.Op’.
Here is an example of ‘.Xo’ using the space mode macro to turn spacing off:
.Sm off
.It Xo Sy I Ar operation
.No \en Ar count No \en
.Xc
.Sm on
Produces
Ioperation\ncount\n
Another one:
.Sm off
.It Cm S No / Ar old_pattern Xo
.No / Ar new_pattern
.No / Op Cm g
.Xc
.Sm on
Produces
S/old_pattern/new_pattern/[g]
Another example of ‘.Xo’ and using enclosure macros: Test the value of an variable.
.It Xo
.Ic .ifndef
.Oo \&! Oc Ns Ar variable
.Op Ar operator variable ...
.Xc
Produces
.ifndef [!]variable [operator variable ...]
All of the above examples have used the ‘.Xo’ macro on the argument list of the ‘.It’ (list-item) macro.
The extend macros are not used very often, and when they are it is usually to extend the list-item
argument list. Unfortunately, this is also where the extend macros are the most finicky. In the first
two examples, spacing was turned off; in the third, spacing was desired in part of the output but not all
of it. To make these macros work in this situation make sure the ‘.Xo’ and ‘.Xc’ macros are placed as
shown in the third example. If the ‘.Xo’ macro is not alone on the ‘.It’ argument list, spacing will be
unpredictable. The ‘.Ns’ (no space macro) must not occur as the first or last macro on a line in this
situation. Out of 900 manual pages (about 1500 actual pages) currently released with BSD only fifteen
use the ‘.Xo’ macro.
PAGE STRUCTURE DOMAIN
Section Headers
The first three ‘.Sh’ section header macros list below are required in every man page. The remaining
section headers are recommended at the discretion of the author writing the manual page. The ‘.Sh’ macro
can take up to nine arguments. It is parsed and but is not callable.
.Sh NAME The ‘.Sh NAME’ macro is mandatory. If not specified, the headers, footers and page layout
defaults will not be set and things will be rather unpleasant. The “NAME” section consists of
at least three items. The first is the ‘.Nm’ name macro naming the subject of the man page.
The second is the Name Description macro, ‘.Nd’, which separates the subject name from the
third item, which is the description. The description should be the most terse and lucid
possible, as the space available is small.
.Sh SYNOPSIS
The “SYNOPSIS” section describes the typical usage of the subject of a man page. The macros
required are either ‘.Nm’, ‘.Cd’, ‘.Fn’, (and possibly ‘.Fo’, ‘.Fc’, ‘.Fd’, ‘.Ft’ macros). The
function name macro ‘.Fn’ is required for manual page sections 2 and 3, the command and general
name macro ‘.Nm’ is required for sections 1, 5, 6, 7, 8. Section 4 manuals require a ‘.Nm’,
‘.Fd’ or a ‘.Cd’ configuration device usage macro. Several other macros may be necessary to
produce the synopsis line as shown below:
cat [-benstuv] [-] file ...
The following macros were used:
.Nm cat
.Op Fl benstuv
.Op Fl
.Ar
Note: The macros ‘.Op’, ‘.Fl’, and ‘.Ar’ recognize the pipe bar character ‘|’, so a command
line such as:
.Op Fl a | Fl b
will not go orbital. Troff normally interprets a | as a special operator. See “PREDEFINED
STRINGS” for a usable | character in other situations.
.Sh DESCRIPTION
In most cases the first text in the “DESCRIPTION” section is a brief paragraph on the command,
function or file, followed by a lexical list of options and respective explanations. To create
such a list, the ‘.Bl’ begin-list, ‘.It’ list-item and ‘.El’ end-list macros are used (see
“Lists and Columns” below).
The following ‘.Sh’ section headers are part of the preferred manual page layout and must be used
appropriately to maintain consistency. They are listed in the order in which they would be used.
.Sh ENVIRONMENT
The “ENVIRONMENT” section should reveal any related environment variables and clues to their
behavior and/or usage.
.Sh EXAMPLES
There are several ways to create examples. See the “EXAMPLES” section below for details.
.Sh FILES
Files which are used or created by the man page subject should be listed via the ‘.Pa’ macro in
the “FILES” section.
.Sh SEE ALSO
References to other material on the man page topic and cross references to other relevant man
pages should be placed in the “SEE ALSO” section. Cross references are specified using the
‘.Xr’ macro. Cross references in the “SEE ALSO” section should be sorted by section number,
and then placed in alphabetical order and comma separated. For example:
ls(1), ps(1), group(5), passwd(5).
At this time refer(1) style references are not accommodated.
.Sh STANDARDS
If the command, library function or file adheres to a specific implementation such as IEEE Std
1003.2 (“POSIX.2”) or ANSI X3.159-1989 (“ANSI C89”) this should be noted here. If the command
does not adhere to any standard, its history should be noted in the “HISTORY” section.
.Sh HISTORY
Any command which does not adhere to any specific standards should be outlined historically in
this section.
.Sh AUTHORS
Credits, if need be, should be placed here.
.Sh DIAGNOSTICS
Diagnostics from a command should be placed in this section.
.Sh ERRORS
Specific error handling, especially from library functions (man page sections 2 and 3) should
go here. The ‘.Er’ macro is used to specify an errno.
.Sh BUGS Blatant problems with the topic go here...
User specified ‘.Sh’ sections may be added, for example, this section was set with:
.Sh PAGE STRUCTURE DOMAIN
Paragraphs and Line Spacing.
.Pp The ‘.Pp’ paragraph command may be used to specify a line space where necessary. The macro is
not necessary after a ‘.Sh’ or ‘.Ss’ macro or before a ‘.Bl’ macro. (The ‘.Bl’ macro asserts a
vertical distance unless the -compact flag is given).
Keeps
The only keep that is implemented at this time is for words. The macros are ‘.Bk’ (begin-keep) and ‘.Ek’
(end-keep). The only option that ‘.Bk’ accepts is -words and is useful for preventing line breaks in the
middle of options. In the example for the make command line arguments (see “What's in a name”), the keep
prevented nroff from placing up the flag and the argument on separate lines. (Actually, the option macro
used to prevent this from occurring, but was dropped when the decision (religious) was made to force
right justified margins in troff as options in general look atrocious when spread across a sparse line.
More work needs to be done with the keep macros, a -line option needs to be added.)
Examples and Displays
There are five types of displays, a quickie one line indented display ‘.D1’, a quickie one line literal
display ‘.Dl’, and a block literal, block filled and block ragged which use the ‘.Bd’ begin-display and
‘.Ed’ end-display macros.
.D1 (D-one) Display one line of indented text. This macro is parsed, but it is not callable.
-ldghfstru
The above was produced by: .Dl -ldghfstru.
.Dl (D-ell) Display one line of indented literal text. The ‘.Dl’ example macro has been used
throughout this file. It allows the indent (display) of one line of text. Its default font is
set to constant width (literal) however it is parsed and will recognized other macros. It is not
callable however.
% ls -ldg /usr/local/bin
The above was produced by .Dl % ls -ldg /usr/local/bin.
.Bd Begin-display. The ‘.Bd’ display must be ended with the ‘.Ed’ macro. Displays may be nested
within displays and lists. ‘.Bd’ has the following syntax:
.Bd display-type [-offset offset_value] [-compact]
The display-type must be one of the following four types and may have an offset specifier for
indentation: ‘.Bd’.
-ragged Display a block of text as typed, right (and left) margin edges are left ragged.
-filled Display a filled (formatted) block. The block of text is formatted (the edges
are filled - not left unjustified).
-literal Display a literal block, useful for source code or simple tabbed or spaced text.
-file file_name The file name following the -file flag is read and displayed. Literal mode is
asserted and tabs are set at 8 constant width character intervals, however any
troff/-mdoc commands in file will be processed.
-offset string If -offset is specified with one of the following strings, the string is
interpreted to indicate the level of indentation for the forthcoming block of
text:
left Align block on the current left margin, this is the default mode of
‘.Bd’.
center Supposedly center the block. At this time unfortunately, the block
merely gets left aligned about an imaginary center margin.
indent Indents by one default indent value or tab. The default indent
value is also used for the ‘.D1’ display so one is guaranteed the
two types of displays will line up. This indent is normally set to
6n or about two thirds of an inch (six constant width characters).
indent-two Indents two times the default indent value.
right This left aligns the block about two inches from the right side of
the page. This macro needs work and perhaps may never do the right
thing by troff.
.Ed End-display.
Font Modes
There are five macros for changing the appearance of the manual page text:
.Em Text may be stressed or emphasized with the ‘.Em’ macro. The usual font for emphasis is italic.
Usage: .Em argument ...
.Em does not does not
.Em exceed 1024 .
exceed 1024.
.Em vide infra ) ) ,
vide infra)),
The ‘.Em’ macro is parsed and is callable. It is an error to call ‘.Em’ without arguments.
.Li The ‘.Li’ literal macro may be used for special characters, variable constants, anything which
should be displayed as it would be typed.
Usage: .Li argument ...
.Li \en \n
.Li M1 M2 M3 ;
M1 M2 M3;
.Li cntrl-D ) ,
cntrl-D),
.Li 1024 ...
1024 ...
The ‘.Li’ macro is parsed and is callable.
.Sy The symbolic emphasis macro is generally a boldface macro in either the symbolic sense or the
traditional English usage.
Usage: .Sy symbol ...
.Sy Important Notice
Important Notice
The ‘.Sy’ macro is parsed and is callable. Arguments to ‘.Sy’ may be quoted.
.Bf Begin font mode. The ‘.Bf’ font mode must be ended with the ‘.Ef’ macro. Font modes may be
nested within other font modes. ‘.Bf’ has the following syntax:
.Bf font-mode
The font-mode must be one of the following three types: ‘.Bf’.
Em | -emphasis Same as if the ‘.Em’ macro was used for the entire block of text.
Li | -literal Same as if the ‘.Li’ macro was used for the entire block of text.
Sy | -symbolic Same as if the ‘.Sy’ macro was used for the entire block of text.
.Ef End font mode.
Tagged Lists and Columns
There are several types of lists which may be initiated with the ‘.Bl’ begin-list macro. Items within
the list are specified with the ‘.It’ item macro and each list must end with the ‘.El’ macro. Lists may
be nested within themselves and within displays. Columns may be used inside of lists, but lists are
unproven inside of columns.
In addition, several list attributes may be specified such as the width of a tag, the list offset, and
compactness (blank lines between items allowed or disallowed). Most of this document has been formatted
with a tag style list (-tag). For a change of pace, the list-type used to present the list-types is an
over-hanging list (-ohang). This type of list is quite popular with TeX users, but might look a bit
funny after having read many pages of tagged lists. The following list types are accepted by ‘.Bl’:
-bullet
-item
-enum
These three are the simplest types of lists. Once the ‘.Bl’ macro has been given, items in the list are
merely indicated by a line consisting solely of the ‘.It’ macro. For example, the source text for a
simple enumerated list would look like:
.Bl -enum -compact
.It
Item one goes here.
.It
And item two here.
.It
Lastly item three goes here.
.El
The results:
1. Item one goes here.
2. And item two here.
3. Lastly item three goes here.
A simple bullet list construction:
.Bl -bullet -compact
.It
Bullet one goes here.
.It
Bullet two here.
.El
Produces:
• Bullet one goes here.
• Bullet two here.
-tag
-diag
-hang
-ohang
-inset
These list-types collect arguments specified with the ‘.It’ macro and create a label which may be inset
into the forthcoming text, hanged from the forthcoming text, overhanged from above and not indented or
tagged. This list was constructed with the ‘-ohang’ list-type. The ‘.It’ macro is parsed only for the
inset, hang and tag list-types and is not callable. Here is an example of inset labels:
Tag The tagged list (also called a tagged paragraph) is the most common type of list used in the
Berkeley manuals.
Diag Diag lists create section four diagnostic lists and are similar to inset lists except callable
macros are ignored.
Hang Hanged labels are a matter of taste.
Ohang Overhanging labels are nice when space is constrained.
Inset Inset labels are useful for controlling blocks of paragraphs and are valuable for converting
-mdoc manuals to other formats.
Here is the source text which produced the above example:
.Bl -inset -offset indent
.It Em Tag
The tagged list (also called a tagged paragraph) is the
most common type of list used in the Berkeley manuals.
.It Em Diag
Diag lists create section four diagnostic lists
and are similar to inset lists except callable
macros are ignored.
.It Em Hang
Hanged labels are a matter of taste.
.It Em Ohang
Overhanging labels are nice when space is constrained.
.It Em Inset
Inset labels are useful for controlling blocks of
paragraphs and are valuable for converting
.Nm -mdoc
manuals to other formats.
.El
Here is a hanged list with two items:
Hanged labels appear similar to tagged lists when the label is smaller than the label width.
Longer hanged list labels blend in to the paragraph unlike tagged paragraph labels.
And the unformatted text which created it:
.Bl -hang -offset indent
.It Em Hanged
labels appear similar to tagged lists when the
label is smaller than the label width.
.It Em Longer hanged list labels
blend in to the paragraph unlike
tagged paragraph labels.
.El
The tagged list which follows uses an optional width specifier to control the width of the tag.
SL sleep time of the process (seconds blocked)
PAGEIN number of disk I/O's resulting from references by the process to pages not loaded in core.
UID numerical user-id of process owner
PPID numerical id of parent of process process priority (non-positive when in non-interruptible
wait)
The raw text:
.Bl -tag -width "PAGEIN" -compact -offset indent
.It SL
sleep time of the process (seconds blocked)
.It PAGEIN
number of disk
.Tn I/O Ns 's
resulting from references
by the process to pages not loaded in core.
.It UID
numerical user-id of process owner
.It PPID
numerical id of parent of process process priority
(non-positive when in non-interruptible wait)
.El
Acceptable width specifiers:
-width Fl sets the width to the default width for a flag. All callable macros have a default
width value. The ‘.Fl’, value is presently set to ten constant width characters or
about five sixth of an inch.
-width 24n sets the width to 24 constant width characters or about two inches. The ‘n’ is
absolutely necessary for the scaling to work correctly.
-width ENAMETOOLONG
sets width to the constant width length of the string given.
-width "int mkfifo"
again, the width is set to the constant width of the string given.
If a width is not specified for the tag list type, the first time ‘.It’ is invoked, an attempt is made to
determine an appropriate width. If the first argument to ‘.It’ is a callable macro, the default width
for that macro will be used as if the macro name had been supplied as the width. However, if another
item in the list is given with a different callable macro name, a new and nested list is assumed.
PREDEFINED STRINGS
The following strings are predefined as may be used by preceding with the troff string interpreting
sequence ‘\*(xx’ where xx is the name of the defined string or as ‘\*x’ where x is the name of the
string. The interpreting sequence may be used any where in the text.
String Nroff Troff
<= <= ≤
>= >= ≥
Rq '' ”
Lq `` “
ua ^ ↑
aa ' ´
ga ` `
q " "
Pi pi π
Ne != ≠
Le <= ≤
Ge >= ≥
Lt < >
Gt > <
Pm +- ±
If infinity ∞
Na NaN NaN
Ba | |
Note: The string named ‘q’ should be written as ‘\*q’ since it is only one char.
DIAGNOSTICS
The debugging facilities for -mdoc are limited, but can help detect subtle errors such as the collision
of an argument name with an internal register or macro name. (A what?) A register is an arithmetic
storage class for troff with a one or two character name. All registers internal to -mdoc for troff and
ditroff are two characters and of the form <upper_case><lower_case> such as ‘Ar’,
<lower_case><upper_case> as ‘aR’ or <upper or lower letter><digit> as ‘C1’. And adding to the muddle,
troff has its own internal registers all of which are either two lower case characters or a dot plus a
letter or meta-character character. In one of the introduction examples, it was shown how to prevent the
interpretation of a macro name with the escape sequence ‘\&’. This is sufficient for the internal
register names also.
If a non-escaped register name is given in the argument list of a request unpredictable behavior will
occur. In general, any time huge portions of text do not appear where expected in the output, or small
strings such as list tags disappear, chances are there is a misunderstanding about an argument type in
the argument list. Your mother never intended for you to remember this evil stuff - so here is a way to
find out whether or not your arguments are valid: The ‘.Db’ (debug) macro displays the interpretation of
the argument list for most macros. Macros such as the ‘.Pp’ (paragraph) macro do not contain debugging
information. All of the callable macros do, and it is strongly advised whenever in doubt, turn on the
‘.Db’ macro.
Usage: .Db [on | off]
An example of a portion of text with the debug macro placed above and below an artificially created
problem (a flag argument ‘aC’ which should be ‘\&aC’ in order to work):
.Db on
.Op Fl aC Ar file )
.Db off
The resulting output:
DEBUGGING ON
DEBUG(argv) MACRO: `.Op' Line #: 2
Argc: 1 Argv: `Fl' Length: 2
Space: `' Class: Executable
Argc: 2 Argv: `aC' Length: 2
Space: `' Class: Executable
Argc: 3 Argv: `Ar' Length: 2
Space: `' Class: Executable
Argc: 4 Argv: `file' Length: 4
Space: ` ' Class: String
Argc: 5 Argv: `)' Length: 1
Space: ` ' Class: Closing Punctuation or suffix
MACRO REQUEST: .Op Fl aC Ar file )
DEBUGGING OFF
The first line of information tells the name of the calling macro, here ‘.Op’, and the line number it
appears on. If one or more files are involved (especially if text from another file is included) the
line number may be bogus. If there is only one file, it should be accurate. The second line gives the
argument count, the argument (‘Fl’) and its length. If the length of an argument is two characters, the
argument is tested to see if it is executable (unfortunately, any register which contains a non-zero
value appears executable). The third line gives the space allotted for a class, and the class type. The
problem here is the argument aC should not be executable. The four types of classes are string,
executable, closing punctuation and opening punctuation. The last line shows the entire argument list as
it was read. In this next example, the offending ‘aC’ is escaped:
.Db on
.Em An escaped \&aC
.Db off
DEBUGGING ON
DEBUG(fargv) MACRO: `.Em' Line #: 2
Argc: 1 Argv: `An' Length: 2
Space: ` ' Class: String
Argc: 2 Argv: `escaped' Length: 7
Space: ` ' Class: String
Argc: 3 Argv: `aC' Length: 2
Space: ` ' Class: String
MACRO REQUEST: .Em An escaped &aC
DEBUGGING OFF
The argument ‘\&aC’ shows up with the same length of 2 as the ‘\&’ sequence produces a zero width, but a
register named ‘\&aC’ was not found and the type classified as string.
Other diagnostics consist of usage statements and are self explanatory.
GROFF, TROFF AND NROFF
The -mdoc package does not need compatibility mode with groff.
The package inhibits page breaks, and the headers and footers which normally occur at those breaks with
nroff, to make the manual more efficient for viewing on-line. At the moment, groff with -Tascii does
eject the imaginary remainder of the page at end of file. The inhibiting of the page breaks makes
nroff'd files unsuitable for hardcopy. There is a register named ‘cR’ which can be set to zero in the
site dependent style file /usr/src/share/tmac/doc-nroff to restore the old style behavior.
FILES
/usr/share/tmac/tmac.doc manual macro package
/usr/share/misc/mdoc.template
template for writing a man page
/usr/share/examples/mdoc/* several example man pages
SEE ALSO
man(1), troff(1), mdoc(7)
BUGS
Undesirable hyphenation on the dash of a flag argument is not yet resolved, and causes occasional mishaps
in the “DESCRIPTION” section. (line break on the hyphen).
Predefined strings are not declared in documentation.
Section 3f has not been added to the header routines.
‘.Nm’ font should be changed in “NAME” section.
‘.Fn’ needs to have a check to prevent splitting up if the line length is too short. Occasionally it
separates the last parenthesis, and sometimes looks ridiculous if a line is in fill mode.
The method used to prevent header and footer page breaks (other than the initial header and footer) when
using nroff occasionally places an unsightly partially filled line (blank) at the would be bottom of the
page.
The list and display macros to not do any keeps and certainly should be able to.
Debian December 30, 1993 MDOC.SAMPLES(7)