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:

To prevent a two character string from being interpreted as a macro name, precede the string with the escape sequence ‘\&’:

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:

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:

If the ‘\’ or quotes were omitted, ‘.Fn’ would see three arguments and the result would be:

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.

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.

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:

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:

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:

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:

The result is:

The punctuation is not recognized and all is output in the literal font. If the punctuation is separated by a leading white space:

The result is:

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’.

Address Macro

The address macro identifies an address construct of the form addr1[,addr2[,addr3]].

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.

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.

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).

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’.

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.

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.

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.

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.

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.

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:

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).

The ‘.Ft’ request is not callable by other macros.

Interactive Commands

The ‘.Ic’ macro designates an interactive or internal command.

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.

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.

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.

The ‘.Pa’ macro is parsed and is callable.

Variables

Generic variable reference:

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.

The ‘.Xr’ macro is parsed and is callable. It is an error to call ‘.Xr’ without any arguments.

AT&T Macro

Usage: .At [v6 | v7 | 32v | V.1 | V.4] ...

The ‘.At’ macro is not parsed and not callable. It accepts at most two arguments.

BSD Macro

The ‘.Bx’ macro is parsed and is callable.

FreeBSD Macro

Usage: .Fx Version.release ...

The ‘.Fx’ macro is not parsed and not callable. It accepts at most two arguments.

UNIX Macro

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.

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:

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:

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.

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.

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.

‘.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.

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

Another one:

.Sm off
.It Cm S No / Ar old_pattern Xo
.No / Ar new_pattern
.No / Op Cm g
.Xc
.Sm on

Produces

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

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.

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.