groff_mdoc(7)

Name
groff_mdoc - compose BSD-style manual (man) pages with GNU roff

Synopsis
groff -mdoc file ...

Description
The GNU implementation of the mdoc macro package is part of the groff(1) document formatting system. mdoc is a structurally- and semantically-oriented package for writing UNIX manual pages with troff(1). Its predecessor, the man(7) package, primarily addressed page layout and presentational concerns, leaving the selection of fonts and other typesetting details to the individual author. This discretion has led to divergent styling practices among authors using it.

mdoc organizes its macros into domains. The page structure domain lays out the page and comprises titles, section headings, displays, and lists. The general text domain supplies macros to quote or style text, or to interpolate common noun phrases. The manual domain offers semantic macros corresponding to the terminology used by practitioners in discussion of UNIX commands, routines, and files. Manual domain macros distinguish command-line arguments and options, function names, function parameters, pathnames, variables, cross references to other manual pages, and so on. These terms are meaningful both to the author and the readers of a manual page. It is hoped that the resulting increased consistency of the man page corpus will enable easier translation to future documentation tools.

Throughout UNIX documentation, a manual entry is referred to simply as a “man page”, regardless of its length, without gendered implication, and irrespective of the macro package selected for its composition.

Getting started
The mdoc package attempts to simplify man page authorship and maintenance without requiring mastery of the roff language. This document presents only essential facts about roff. For further background, including a discussion of basic typographical concepts like “breaking”, “filling”, and “adjustment”, see roff(7). Specialized units of measurement also arise, namely ens, vees, inches, and points, abbreviated “n”, “v”, “i”, and “p”, respectively; see section Measurements of groff(7).

For brief examples, we employ an arrow notation illustrating a transformation of input on the left to rendered output on the right. Consider the .“” macro, which double-quotes its arguments.
.Dq man page
    → “man page”

  Usage
An mdoc macro is called by placing the roff control character, ‘’. (dot) at the beginning of a line followed by its name. In this document, we often discuss a macro name with this leading dot to identify it clearly, but the dot is not part of its name. Space or tab characters can separate the dot from the macro name. Arguments may follow, separated from the macro name and each other by spaces, but not tabs. The dot at the beginning of the line prepares the formatter to expect a macro name. A dot followed immediately by a newline is ignored; this is called the empty request. To begin an input line with a dot (or a neutral apostrophe ‘'’) in some context other than a macro call, precede it with the ‘\&’ escape sequence; this is a dummy character, not formatted for output. The backslash is the roff escape character; it can appear anywhere and it always followed by at least one more character. If followed by a newline, the backslash escapes the input line break; you can thus keep input lines to a reasonable length without affecting their interpretation.

Macros in GNU troff accept an unlimited number of arguments, in contrast to other troffs that often can't handle more than nine. In limited cases, arguments may be continued or extended on the next input line without resort to the ‘\newline’ escape sequence; see subsection Extended arguments below. Neutral double quotes " can be used to group multiple words into an argument; see subsection Passing space characters in an argument below.

Most of mdoc's general text and manual domain macros parse their argument lists for callable macro names. This means that an argument in the list matching a general text or manual domain macro name (and defined to be callable) will be called with the remaining arguments when it is encountered. In such cases, the argument, although the name of a macro, is not preceded by a dot. Macro calls can thus be nested. This approach to macro argument processing is a unique characteristic of the mdoc package, not a general feature of roff syntax.

For example, the option macro, .[], may call the flag and argument macros,.- and .file ..., to specify an optional flag with an argument.
.Op Fl s Ar bytes
    → [-s bytes]
To prevent a word from being interpreted as a macro name, precede it with the dummy character.
.Op \&Fl s \&Ar bytes
    → [-s bytes]

In this document, macros whose argument lists are parsed for callable arguments are referred to as parsed, and those that may be called from an argument list are referred to as callable. This usage is a technical faux pas, since all mdoc macros are in fact interpreted (unless prevented with ‘\&’), but as it is cumbersome to constantly refer to macros as “being able to call other macros”, we employ the term “parsed” instead. Except where explicitly stated, all mdoc macros are parsed and callable.

In the following, we term an mdoc macro that starts a line (with a leading dot) a command if a distinction from those appearing as arguments of other macros is necessary.

  Passing space characters in an argument
Sometimes it is desirable to give a macro an argument containing one or more space characters, for instance to specify a particular arrangement of arguments demanded by the macro. Additionally, quoting multi-word arguments that are to be treated the same makes mdoc work faster; macros that parse arguments do so once (at most) for each. For example, the function command. expects its first argument to be the name of a function and any remaining arguments to be function parameters. Because C language standards mandate the inclusion of types and identifiers in the parameter lists of function definitions, each ‘’ parameter after the first will be at least two words in length, as in “int foo”.

There are a few ways to embed a space in a macro argument. One is to use the unadjustable space escape sequence \space. The formatter treats this escape sequence as if it were any other printable character, and will not break a line there as it would a word space when the output line is full. This method is useful for macro arguments that are not expected to straddle an output line boundary, but has a drawback: this space does not adjust as others do when the output line is formatted. An alternative is to use the unbreakable space escape sequence, ‘\~’, which cannot break but does adjust. This groff extension is widely but not perfectly portable. Another method is to enclose the string in double quotes.
.Fn fetch char\ *str
    → fetch(char *str)
.Fn fetch char\~*str
    → fetch(char *str)
.Fn fetch "char *str"
    → fetch(char *str)
If the ‘\’ before the space in the first example or the double quotes in the third example were omitted, ‘.Fn’ would see three arguments, and the result would contain an undesired comma.
.Fn fetch char *str
    → fetch(char, *str)

  Trailing space characters
It is wise to remove trailing spaces from the ends of input lines. Should the need arise to put a formattable space at the end of a line, do so with the unadjustable or unbreakable space escape sequences.

  Formatting the backslash glyph
When you need the roff escape character ‘\’ to appear in the output, use ‘\e’ or ‘\(rs’ instead. Technically, ‘\e’ formats the current escape character; it works reliably as long as no roff request is used to change it, which should never happen in man pages. ‘\(rs’ is a groff special character escape sequence that explicitly formats the “reverse solidus” (backslash) glyph.

  Other possible pitfalls
groff mdoc warns when an empty input line is found outside of a display, a topic presented in subsection Examples and displays below. Use empty requests to space the source document for maintenance.

Leading spaces cause a break and are formatted. Avoid this behaviour if possible. Similarly, do not put more than one space between words in an ordinary text line; they are not “normalized” to a single space as other text formatters might do.

Don't try to use the neutral double quote character ‘"’ to represent itself in an argument. Use the special character escape sequence ‘\(dq’ to format it. Further, this glyph should not be used for conventional quotation; mdoc offers several quotation macros. See subsection Enclosure and quoting macros below.

The formatter attempts to detect the ends of sentences and by default puts the equivalent of two spaces between sentences on the same output line; see roff(7). To defeat this detection in a parsed list of macro arguments, put ‘\&’ before the punctuation mark. Thus,
    The
    .Ql .
    character.
    .Pp
    The
    .Ql \&.
    character.
    .Pp
    .No test .
    test
    .Pp
    .No test.
    test

gives
The ‘’. character

The ‘’. character.

test. test

test. test

as output. As can be seen in the first and third output lines, mdoc handles punctuation characters specially in macro arguments. This will be explained in section General syntax below.

A comment in the source file of a man page can begin with ‘.\"’ at the start of an input line, ‘\"’ after other input, or ‘\#’ anywhere (the last is a groff extension); the remainder of any such line is ignored.

A man page template
Use mdoc to construct a man page from the following template.

    .\" The following three macro calls are required.
    .Dd date
    .Dt topic [section-identifier [section-keyword-or-title]]
    .Os [package-or-operating system [version-or-release]]
    .Sh Name
    .Nm topic
    .Nd summary-description
    .\" The next heading is used in sections 2 and 3.
    .\" .Sh Library
    .\" The next heading is used in sections 1-4, 6, 8, and 9.
    .Sh Synopsis
    .Sh Description
    .\" Uncomment and populate the following sections as needed.
    .\" .Sh "Implementation notes"
    .\" The next heading is used in sections 2, 3, and 9.
    .\" .Sh "Return values"
    .\" The next heading is used in sections 1, 3, 6, and 8.
    .\" .Sh Environment
    .\" .Sh Files
    .\" The next heading is used in sections 1, 6, and 8.
    .\" .Sh "Exit status"
    .\" .Sh Examples
    .\" The next heading is used in sections 1, 4, 6, 8, and 9.
    .\" .Sh Diagnostics
    .\" .Sh Compatibility
    .\" The next heading is used in sections 2, 3, 4, and 9.
    .\" .Sh Errors
    .\" .Sh "See also"
    .\" .Sh Standards
    .\" .Sh History
    .\" .Sh Authors
    .\" .Sh Caveats
    .\" .Sh Bugs

The first items in the template are the commands .Dd, .Dt, and .Os. They identify the page and are discussed below in section Title macros.

The remaining items in the template are section headings (.Sh); of which Name and Description are mandatory. These headings are discussed in section Page structure domain, which follows section Manual domain. Familiarize yourself with manual domain macros first; we use them to illustrate the use of page structure domain macros.

Conventions
In the descriptions of macros below, square brackets surround optional arguments. An ellipsis (‘...’) represents repetition of the preceding argument zero or more times. Alternative values of a parameter are separated with ‘|’. If a mandatory parameter can take one of several alternative values, use braces to enclose the set, with spaces and ‘|’ separating the items.
ztar
    {c | x} [-w [-y | -z]] [-f archive] member ...
An alternative to using braces is to separately synopsize distinct operation modes, particularly if the list of valid optional arguments is dependent on the user's choice of a mandatory parameter.
ztar
    c [-w [-y | -z]] [-f archive] member ...
ztar
    x [-w [-y | -z]] [-f archive] member ...

Most macros affect subsequent arguments until another macro or a newline is encountered. For example, ‘.Li ls Bq Ar file’ doesn't produce ‘ls [file]’, but ‘ls [file]’. Consequently, a warning message is emitted for many commands if the first argument is itself a macro, since it cancels the effect of the preceding one. On rare occasions, you might want to format a word along with surrounding brackets as a literal.
.Li "ls [file]"
    → ls [file] # list any files named e, f, i, or l

Many macros possess an implicit width, used when they are contained in lists and displays. If you avoid relying on these default measurements, you escape potential conflicts with site-local modifications of the mdoc package. Explicit -width and -offset arguments to the .Bl and .Bd macros are preferable.

Title macros
We present the mandatory title macros first due to their importance even though they formally belong to the page structure domain macros. They designate the topic, date of last revision, and the operating system or software project associated with the page. Call each once at the beginning of the document. They populate the page headers and footers, which are in roff parlance termed “titles”.

.Dd date This first macro of any mdoc manual records the last modification date of the document source. Arguments are concatenated and separated with space characters.

    Historically, date was written in U.S. traditional format, “ Month day, year ” where Month is the full month name in English, day an integer without a leading zero, and year the four-digit year. This localism is not enforced, however. You may prefer ISO 8601 format, YYYY-MM-DD. A date of the form ‘$Mdocdate: Month day year $’ is also recognized. It is used in OpenBSD manuals to automatically insert the current date when committing.

    This macro is neither callable nor parsed.

.Dt topic [section-identifier [section-keyword-or-title]]
    topic is the subject of the man page. A section-identifier that begins with an integer in the range 1–9 or is one of the words ‘unass’, ‘draft’, or ‘paper’ selects a predefined section title. This use of “section” has nothing to do with the section headings otherwise discussed in this page; it arises from the organizational scheme of printed and bound Unix manuals.

    In this implementation, the following titles are defined for integral section numbers.

        1 |
        2 |
        3 |
        4 |
        5 |
        6 |
        7 |
        8 |
        9 |

    A section title may be arbitrary or one of the following abbreviations.

        USD |
        PS1 |
        AMD |
        SMM |
        URM |
        PRM |
        KM |
        IND |
        LOCAL |
        CON |

    For compatibility, ‘MMI’ can be used for ‘IND’, and ‘LOC’ for ‘LOCAL’. Values from the previous table will specify a new section title. If section-keyword-or-title designates a computer architecture recognized by groff mdoc, its value is prepended to the default section title as specified by the second parameter. By default, the following architecture keywords are defined.

    acorn26, acorn32, algor, alpha, amd64, amiga, amigappc, arc, arm, arm26, arm32, armish, atari, aviion, beagle, bebox, cats, cesfic, cobalt, dreamcast, emips, evbarm, evbmips, evbppc, evbsh3, ews4800mips, hp300, hp700, hpcarm, hpcmips, hpcsh, hppa, hppa64, i386, ia64, ibmnws, iyonix, landisk, loongson, luna68k, luna88k, m68k, mac68k, macppc, mips, mips64, mipsco, mmeye, mvme68k, mvme88k, mvmeppc, netwinder, news68k, newsmips, next68k, ofppc, palm, pc532, playstation2, pmax, pmppc, powerpc, prep, rs6000, sandpoint, sbmips, sgi, sgimips, sh3, shark, socppc, solbourne, sparc, sparc64, sun2, sun3, tahoe, vax, x68k, x86_64, xen, zaurus

    If a section title is not determined after the above matches have been attempted, section-keyword-or-title is used.

    The effects of varying ‘.Dt’ arguments on the page header content are shown below. Observe how ‘\&’ prevents the numeral 2 from being used to look up a predefined section title.

        .Dt foo 2 | → | foo(2) | System Calls Manual | foo(2)
        .Dt foo 2 m68k | → | foo(2) | m68k System Calls Manual | foo(2)
        .Dt foo 2 baz | → | foo(2) | System Calls Manual | foo(2)
        .Dt foo \&2 baz | → | foo(2) | baz | foo(2)
        .Dt foo "" baz | → | foo | baz | foo
        .Dt foo M Z80 | → | foo(M) | Z80 | foo(M)

    roff strings define section titles and architecture identifiers. Site-specific additions might be found in the file mdoc.local; see section Files below.

    This macro is neither callable nor parsed.

.Os [operating-system-or-package-name [version-or-release]]
    This macro associates the document with a software distribution. When composing a man page to be included in the base installation of an operating system, do not provide an argument; mdoc will supply it. In this implementation, that default is “”. It may be overridden in the site configuration file, mdoc.local; see section Files below. A portable software package maintaining its own man pages can supply its name and version number or release identifier as optional arguments. A version-or-release argument should use the standard nomenclature for the software specified. In the following table, recognized version-or-release arguments for some predefined operating systems are listed. As with .Dt, site additions might be defined in mdoc.local.

    ATT 7th, 7, III, 3, V, V.2, V.3, V.4

    BSD 3, 4, 4.1, 4.2, 4.3, 4.3t, 4.3T, 4.3r, 4.3R, 4.4

    NetBSD
        0.8, 0.8a, 0.9, 0.9a, 1.0, 1.0a, 1.1, 1.2, 1.2a, 1.2b, 1.2c, 1.2d, 1.2e, 1.3, 1.3a, 1.4, 1.4.1, 1.4.2, 1.4.3, 1.5, 1.5.1, 1.5.2, 1.5.3, 1.6, 1.6.1, 1.6.2, 1.6.3, 2.0, 2.0.1, 2.0.2, 2.0.3, 2.1, 3.0, 3.0.1, 3.0.2, 3.0.3, 3.1, 3.1.1, 4.0, 4.0.1, 5.0, 5.0.1, 5.0.2, 5.1, 5.1.2, 5.1.3, 5.1.4, 5.2, 5.2.1, 5.2.2, 6.0, 6.0.1, 6.0.2, 6.0.3, 6.0.4, 6.0.5, 6.0.6, 6.1, 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 7.0, 7.0.1, 7.0.2, 7.1, 7.1.1, 7.1.2, 7.2, 8.0, 8.1

    FreeBSD
        1.0, 1.1, 1.1.5, 1.1.5.1, 2.0, 2.0.5, 2.1, 2.1.5, 2.1.6, 2.1.7, 2.2, 2.2.1, 2.2.2, 2.2.5, 2.2.6, 2.2.7, 2.2.8, 2.2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 4.0, 4.1, 4.1.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.6.2, 4.7, 4.8, 4.9, 4.10, 4.11, 5.0, 5.1, 5.2, 5.2.1, 5.3, 5.4, 5.5, 6.0, 6.1, 6.2, 6.3, 6.4, 7.0, 7.1, 7.2, 7.3, 7.4, 8.0, 8.1, 8.2, 8.3, 8.4, 9.0, 9.1, 9.2, 9.3, 10.0, 10.1, 10.2, 10.3, 10.4, 11.0, 11.1, 11.2, 11.3, 12.0, 12.1

    OpenBSD
        2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6

    DragonFly
        1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.8.1, 1.9, 1.10, 1.11, 1.12, 1.12.2, 1.13, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 2.9.1, 2.10, 2.10.1, 2.11, 2.12, 2.13, 3.0, 3.0.1, 3.0.2, 3.1, 3.2, 3.2.1, 3.2.2, 3.3, 3.4, 3.4.1, 3.4.2, 3.4.3, 3.5, 3.6, 3.6.1, 3.6.2, 3.7, 3.8, 3.8.1, 3.8.2, 4.0, 4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.1, 4.2, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.3, 4.4, 4.4.1, 4.4.2, 4.4.3, 4.5, 4.6, 4.6.1, 4.6.2, 4.7, 4.8, 4.8.1, 4.9, 5.0, 5.0.1, 5.0.2, 5.1, 5.2, 5.2.1, 5.2.2, 5.3, 5.4, 5.4.1, 5.4.2, 5.4.3, 5.5, 5.6, 5.6.1, 5.6.2

    Darwin
        8.0.0, 8.1.0, 8.2.0, 8.3.0, 8.4.0, 8.5.0, 8.6.0, 8.7.0, 8.8.0, 8.9.0, 8.10.0, 8.11.0, 9.0.0, 9.1.0, 9.2.0, 9.3.0, 9.4.0, 9.5.0, 9.6.0, 9.7.0, 9.8.0, 10.0.0, 10.1.0, 10.2.0, 10.3.0, 10.4.0, 10.5.0, 10.6.0, 10.7.0, 10.8.0, 11.0.0, 11.1.0, 11.2.0, 11.3.0, 11.4.0, 11.5.0, 12.0.0, 12.1.0, 12.2.0, 13.0.0, 13.1.0, 13.2.0, 13.3.0, 13.4.0, 14.0.0, 14.1.0, 14.2.0, 14.3.0, 14.4.0, 14.5.0, 15.0.0, 15.1.0, 15.2.0, 15.3.0, 15.4.0, 15.5.0, 15.6.0, 16.0.0, 16.1.0, 16.2.0, 16.3.0, 16.4.0, 16.5.0, 16.6.0, 17.0.0, 17.1.0, 17.2.0, 17.3.0, 17.4.0, 17.5.0, 17.6.0, 17.7.0, 18.0.0, 18.1.0, 18.2.0, 18.3.0, 18.4.0, 18.5.0, 18.6.0, 18.7.0, 19.0.0, 19.1.0, 19.2.0

    Historically, the first argument used with .Dt was BSD or ATT. An unrecognized version argument after ATT is replaced with “UNIX”; for other predefined abbreviations, it is ignored and a warning diagnostic emitted. Otherwise, unrecognized arguments are displayed verbatim in the page footer. For instance, this page uses “.Os groff 1.23.0” whereas a locally produced page might employ “.Os "UXYZ CS Department"”, omitting versioning.

    This macro is neither callable nor parsed.

Introduction to 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 command 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 macros are themselves a type of command; the general syntax for a troff command is:

.Xx argument1 argument2 ...

‘.Xx’ is a macro command, and anything following it are arguments to be processed. In the second case, the description of a UNIX command using the manual domain 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 meta arguments; in this example, the user has to replace the meta expressions given in angle brackets with real file names. Note that in this document meta arguments are used to describe mdoc commands; in most man pages, meta variables are not specifically written with angle brackets. The macros that formatted the above example:

    .Nm filter
    .Op Fl flag
    .Ao Ar infile Ac Ao Ar outfile Ac

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 ‘file ...’ 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 Ns = Ns Ar value
    .Bk
    .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; most notably, ‘.Ar’, ‘.Fl’, ‘.Nm’, and ‘.Pa’ differ only when called without arguments; and ‘.Fn’ and ‘.Xr’ impose an order on their argument lists. All manual domain macros are capable of recognizing and properly handling punctuation, provided each punctuation character is separated by a leading space. If a command is given:

    .Ar sptr, ptr),

The result is:

    sptr, ptr),

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

    .Ar sptr , ptr ) ,

The result is:

    sptr, ptr),

The punctuation is now recognized and output in the default font distinguishing it from the argument strings. To remove the special meaning from a punctuation character, escape it with ‘\&’.

The following punctuation characters are recognized by mdoc:
. |, |: |; | (
) | [|] |? |!

troff is limited as a macro language, and has difficulty when presented with a string containing certain mathematical, logical, or quotation character sequences:

    {+,-,/,*,%,<,>,<=,>=,=,==,&,`,',"}

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 manual domain macro displayed below, ‘.Ad’.

Manual domain

  Addresses
The address macro identifies an address construct.

    Usage: .Ad <address> ...

.Ad addr1
    addr1
.Ad addr1 .
    addr1.
.Ad addr1 , file2
    addr1, file2
.Ad f1 , f2 , f3 :
    f1, f2, f3:
.Ad addr ) ) ,
    addr)),

The default width is 12n.

  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.

    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 default width is 12n.

In a section titled “Authors”, ‘’ causes a break, allowing each new name to appear on its own line. If this is not desirable,

    .An -nosplit

call will turn this off. To turn splitting back on, write

    .An -split

  Arguments
The .Ar argument macro may be used whenever an argument is referenced. If called without arguments, ‘file ...’ is output. This places the ellipsis in italics, which is ugly and incorrect, and will be noticed on terminals that underline text instead of using an oblique typeface. We recommend using ‘.Ar file No ...’ instead.

    Usage: .Ar [<argument>] ...

.Ar file ...
.Ar file ...
    file ...
.Ar file1
    file1
.Ar file1 .
    file1.
.Ar file1 file2
    file1 file2
.Ar f1 f2 f3 :
    f1 f2 f3:
.Ar file ) ) ,
    file)),

The default width is 12n.

  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.

    Usage: .Cd <argument> ...

.Cd "device le0 at scode?"
    device le0 at scode?

In a section titled “Synopsis”, ‘’ causes a break before and after its arguments.

The default width is 12n.

  Command Modifiers
The command modifier is identical to the ‘.Fl’ (flag) command with the exception that the ‘.Cm’ macro does not assert a dash in front of every argument. Traditionally flags are marked by the preceding dash, however, 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.

The default width is 10n.

  Defined Variables
A variable (or constant) that is defined in an include file is specified by the macro ‘.Dv’.

    Usage: .Dv <defined-variable> ...

.Dv MAXHOSTNAMELEN
    MAXHOSTNAMELEN
.Dv TIOCGPGRP )
    TIOCGPGRP)

The default width is 12n.

  Errnos
The ‘.Er’ errno macro specifies the error return value for section 2, 3, and 9 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 <errno type> ...

.Er ENOENT
    ENOENT
.Er ENOENT ) ;
    ENOENT);
.Bq Er ENOTDIR
    [ENOTDIR]

The default width is 17n.

  Environment Variables
The ‘.Ev’ macro specifies an environment variable.

    Usage: .Ev <argument> ...

.Ev DISPLAY
    DISPLAY
.Ev PATH .
    PATH.
.Ev PRINTER ) ) ,
    PRINTER)),

The default width is 15n.

  Flags
The ‘.Fl’ macro handles command-line flags. It prepends a dash, ‘-’, to the flag. For interactive command flags that 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.
.Cm cfv .
    cfv.
.Fl s v t
    -s -v -t
.Fl - ,
    --,
.Fl xyz ) ,
    -xyz),
.Fl |
    |

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 default width is 12n.

  Function Declarations
The ‘.Fd’ macro is used in the Synopsis section with section two or three functions. It is neither callable nor parsed.

    Usage: .Fd <argument> ...

.Fd "#include <sys/types.h>"
    #include <sys/types.h>

In a section titled “Synopsis”, ‘Fd’ causes a break if a function has already been presented and a break has not occurred, leaving vertical space between one function declaration and the next.

In a section titled “Synopsis”, the ‘’ macro represents the #include statement, and is the short form of the above example. It specifies the C header file as being included in a C program. It also causes a break.

While not in the “Synopsis” section, it represents the header file enclosed in angle brackets.

    Usage: .In <header file>

.In stdio.h
    <stdio.h>
.In stdio.h
    <stdio.h>

  Function Types
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 BSD kernel normal form) for the “Synopsis” of sections two and three. (It causes a break, allowing the function name to appear on the next line.)

    Usage: .Ft <type> ...

.Ft struct stat
    struct stat

  Functions (Library Routines)
The ‘.Fn’ macro is modeled on ANSI C conventions.

    Usage: .Fn <function> [<parameter>] ...

.Fn getchar
    getchar()
.Fn strlen ) ,
    strlen()),
.Fn align "char *ptr" ,
    align(char *ptr),

Note that any call to another macro signals the end of the ‘.Fn’ call (it will insert a closing parenthesis at that point).

For functions with many parameters (which is rare), the macros ‘.Fo’ (function open) and ‘.Fc’ (function close) may be used with ‘.Fa’ (function argument).

Example:

    .Ft int
    .Fo 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)

Typically, in a “Synopsis” section, the function delcaration will begin the line. If more than one function is presented in the “Synopsis” section and a function type has not been given, a break will occur, leaving vertical space between the current and prior function names.

The default width values of ‘.Fn’ and ‘.Fo’ are 12n and 16n, respectively.

  Function Arguments
The ‘.Fa’ macro is used to refer to function arguments (parameters) outside of the Synopsis section of the manual or inside the Synopsis section if the enclosure macros ‘.Fo’ and ‘.Fc’ instead of ‘.Fn’ are 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

The default width is 12n.

  Return Values
The ‘.Rv’ macro generates text for use in the Return values section.

    Usage: .Rv [-std] [<function> ...]

For example, ‘.Rv -std atexit’ produces:

The -std option is valid only for manual page sections 2 and 3. Currently, this macro does nothing if used without the -std flag.

  Exit Status
The ‘.Ex’ macro generates text for use in the Diagnostics section.

    Usage: .Ex [-std] [<utility> ...]

For example, ‘.Ex -std cat’ produces:

The -std option is valid only for manual page sections 1, 6 and 8. Currently, this macro does nothing if used without the -std flag.

  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

The default width is 12n.

  Library Names
The ‘.Lb’ macro is used to specify the library where a particular function is compiled in.

    Usage: .Lb <argument> ...

Available arguments to ‘.Lb’ and their results are:

libarchive
    libarchive
libarm
    libarm
libarm32
    libarm32
libbluetooth
    libbluetooth
libbsm
    libbsm
libc
    libc
libc_r
    libc_r
libcalendar
    libcalendar
libcam
    libcam
libcdk
    libcdk
libcipher
    libcipher
libcompat
    libcompat
libcrypt
    libcrypt
libcurses
    libcurses
libdevinfo
    libdevinfo
libdevstat
    libdevstat
libdisk
    libdisk
libdwarf
    libdwarf
libedit
    libedit
libelf
    libelf
libevent
    libevent
libfetch
    libfetch
libform
    libform
libgeom
    libgeom
libgpib
    libgpib
libi386
    libi386
libintl
    libintl
libipsec
    libipsec
libipx
    libipx
libiscsi
    libiscsi
libjail
    libjail
libkiconv
    libkiconv
libkse
    libkse
libkvm
    libkvm
libm
    libm
libm68k
    libm68k
libmagic
    libmagic
libmd
    libmd
libmemstat
    libmemstat
libmenu
    libmenu
libnetgraph
    libnetgraph
libnetpgp
    libnetpgp
libossaudio
    libossaudio
libpam
    libpam
libpcap
    libpcap
libpci
    libpci
libpmc
    libpmc
libposix
    libposix
libprop
    libprop
libpthread
    libpthread
libpuffs
    libpuffs
librefuse
    librefuse
libresolv
    libresolv
librpcsec_gss
    librpcsec_gss
librpcsvc
    librpcsvc
librt
    librt
libsdp
    libsdp
libssp
    libssp
libSystem
    libSystem
libtermcap
    libtermcap
libterminfo
    libterminfo
libthr
    libthr
libufs
    libufs
libugidfw
    libugidfw
libulog
    libulog
libusbhid
    libusbhid
libutil
    libutil
libvgl
    libvgl
libx86_64
    libx86_64
libz
    libz

Site-specific additions might be found in the file mdoc.local; see section Files below.

In a section titled “Library”, ‘’ causes a break before and after its arguments.

  Literals
The ‘’ literal macro may be used for special characters, symbolic constants, and other syntactical items that should be typed exactly as displayed.

    Usage: .Li <argument> ...

.Li \en
    \n
.Li M1 M2 M3 ;
    M1 M2 M3;
.Li cntrl-D ) ,
    cntrl-D),
.Li 1024 ...
    1024 ...

The default width is 16n.

  Names
The ‘groff_mdoc’ macro is used for the document title or page topic. Upon its first call, it has the peculiarity of remembering its argument, which should always be the topic of the man page. When subsequently called without arguments, ‘groff_mdoc’ regurgitates this initial name for the sole purpose of making less work for the author. Use of ‘groff_mdoc’ is also appropriate when presenting a command synopsis for the topic of a man page in section 1, 6, or 8. Its behavior changes when presented with arguments of various forms.

.Nm groff_mdoc
    groff_mdoc
.Nm groff_mdoc
.Nm \-mdoc
    -mdoc
.Nm foo ) ) ,
    foo)),
.Nm :
    groff_mdoc:

By default, the topic is set in boldface to reflect its prime importance in the discussion. Cross references to other man page topics should use ‘’; including a second argument for the section number enables them to be hyperlinked. By default, cross-referenced topics are set in italics to avoid cluttering the page with boldface.

The default width is 10n.

  Options
The ‘.Op’ macro places option brackets around any remaining arguments on the command line, and places any trailing punctuation outside the brackets. The macros ‘.Oo’ and ‘.Oc’ (which produce an opening and a closing option bracket, respectively) may be used across one or more lines or to specify the exact position of the closing parenthesis.

    Usage: .Op [<option>] ...

.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]
.Li .Op Oo Ao option Ac Oc ...
    .Op [<option>] ...

Here a typical example of the ‘.Oo’ and ‘.Oc’ macros:

    .Oo
    .Op Fl k Ar kilobytes
    .Op Fl i Ar interval
    .Op Fl c Ar count
    .Oc

Produces:

[ [-k kilobytes] [-i interval] [-c count]]

The default width values of ‘.Op’ and ‘.Oo’ are 14n and 10n, respectively.

  Pathnames
The ‘.Pa’ macro formats file specifications. If called without arguments, ‘~’ (recognized by many shells) is output, representing the user's home directory.

    Usage: .Pa [<pathname>] ...

.Pa ~
.Pa /usr/share
    /usr/share
.Pa /tmp/fooXXXXX ) .
    /tmp/fooXXXXX).

The default width is 32n.

  Standards
The ‘.St’ macro replaces standard abbreviations with their formal names.

    Usage: .St <abbreviation> ...

Available pairs for “Abbreviation/Formal Name” are:

ANSI/ISO C

-ansiC
    ansiC
-ansiC-89
    ansiC-89
-isoC
    isoC
-isoC-90
    isoC-90
-isoC-99
    isoC-99
-isoC-2011
    isoC-2011

POSIX Part 1: System API

-iso9945-1-90
    iso9945-1-90
-iso9945-1-96
    iso9945-1-96
-p1003.1
    p1003.1
-p1003.1-88
    p1003.1-88
-p1003.1-90
    p1003.1-90
-p1003.1-96
    p1003.1-96
-p1003.1b-93
    p1003.1b-93
-p1003.1c-95
    p1003.1c-95
-p1003.1g-2000
    p1003.1g-2000
-p1003.1i-95
    p1003.1i-95
-p1003.1-2001
    p1003.1-2001
-p1003.1-2004
    p1003.1-2004
-p1003.1-2008
    p1003.1-2008

POSIX Part 2: Shell and Utilities

-iso9945-2-93
    iso9945-2-93
-p1003.2
    p1003.2
-p1003.2-92
    p1003.2-92
-p1003.2a-92
    p1003.2a-92

X/Open

-susv1
    susv1
-susv2
    susv2
-susv3
    susv3
-susv4
    susv4
-svid4
    svid4
-xbd5
    xbd5
-xcu5
    xcu5
-xcurses4.2
    xcurses4.2
-xns5
    xns5
-xns5.2
    xns5.2
-xpg3
    xpg3
-xpg4
    xpg4
-xpg4.2
    xpg4.2
-xsh5
    xsh5

Miscellaneous

-ieee754
    ieee754
-iso8601
    iso8601
-iso8802-3
    iso8802-3

  Variable Types
The ‘.Vt’ macro may be used whenever a type is referenced. In a section titled “Synopsis”, ‘’ causes a break (useful for old-style C variable declarations).

    Usage: .Vt <type> ...

.Vt extern char *optarg ;
    extern char *optarg;
.Vt FILE *
    FILE *

  Variables
Generic variable reference.

    Usage: .Va <variable> ...

.Va count
    count
.Va settimer ,
    settimer,
.Va "int *prt" ) :
    int *prt):
.Va "char s" ] ) ) ,
    char s])),

The default width is 12n.

  Manual Page Cross References
The ‘.Xr’ macro expects the first argument to be a manual page name. The optional second argument, if a string (defining the manual section), is put into parentheses.

    Usage: .Xr <man page name> [<section>] ...

.Xr mdoc
    mdoc
.Xr mdoc ,
    mdoc,
.Xr mdoc 7
    mdoc(7)
.Xr xinit 1x ;
    xinit(1x);

The default width is 10n.

General text domain

  AT&T Macro

    Usage: .At [<version>] ...

.At AT&T UNIX
.At v6 .
    AT&T UNIX.

The following values for <version> are possible:

    32v, v1, v2, v3, v4, v5, v6, v7, III, V, V.1, V.2, V.3, V.4

  BSD Macro

    Usage: .Bx {-alpha | -beta | -devel} ...
           .Bx [<version> [<release>]] ...

.Bx BSD
.Bx 4.3 .
    4.3BSD.
.Bx -devel
    -develBSD

<version> will be prepended to the string ‘BSD’. The following values for <release> are possible:

    Reno, reno, Tahoe, tahoe, Lite, lite, Lite2, lite2

  NetBSD Macro

    Usage: .Nx [<version>] ...

.Nx NetBSD
.Nx 1.4 .
    NetBSD 1.4.

For possible values of <version> see the description of the ‘.Os’ command above in section Title macros.

  FreeBSD Macro

    Usage: .Fx [<version>] ...

.Fx FreeBSD
.Fx 2.2 .
    FreeBSD 2.2.

For possible values of <version> see the description of the ‘.Os’ command above in section Title macros.

  DragonFly Macro

    Usage: .Dx [<version>] ...

.Dx DragonFly
.Dx 1.4 .
    DragonFly 1.4.

For possible values of <version> see the description of the ‘.Os’ command above in section Title macros.

  OpenBSD Macro

    Usage: .Ox [<version>] ...

.Ox 1.0
    OpenBSD 1.0

  BSD/OS Macro

    Usage: .Bsx [<version>] ...

.Bsx 1.0
    BSD/OS 1.0

  Unix Macro

    Usage: .Ux ...

.Ux UNIX

  Emphasis Macro
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 default width is 10n.

  Font Mode
The ‘.Bf’ font mode must be ended with the ‘.Ef’ macro (the latter takes no arguments). Font modes may be nested within other font modes.

‘.Bf’ has the following syntax:

    .Bf <font mode>

<font mode> must be one of the following three types:

| -emphasis
    Same as if the ‘.Em’ macro was used for the entire block of text.
| -literal
    Same as if the ‘.Li’ macro was used for the entire block of text.
| -symbolic
    Same as if the ‘.Sy’ macro was used for the entire block of text.

Both macros are neither callable nor parsed.

  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 a pair of opening and closing macros that end with the lowercase letters ‘o’ and ‘c’ respectively.

Quote | Open | Close | Function | Result
.Aq | .Ao | .Ac | Angle Bracket Enclosure | <string>
.Bq | .Bo | .Bc | Bracket Enclosure | [string]
.Brq | .Bro | .Brc | Brace Enclosure | {string}
.Dq | .Do | .Dc | Double Quote | “string”
.Eq | .Eo | .Ec | Enclose String (in XY) | XstringY
.Pq | .Po | .Pc | Parenthesis Enclosure | (string)
.Ql |  |  | Quoted Literal | “string” or string
.Qq | .Qo | .Qc | Straight Double Quote | "string"
.Sq | .So | .Sc | Single Quote | ‘string’

All macros ending with ‘q’ and ‘o’ have a default width value of 12n.

.Eo, .Ec
    These macros expect the first argument to be the opening and closing strings, respectively.

.Es, .En
    To work around the nine-argument limit in the original troff program, mdoc supports two other macros that are now obsolete. ‘.Es’ uses its first and second parameters as opening and closing marks which are then used to enclose the arguments of ‘.En’. The default width value is 12n for both macros.

.Eq The first and second arguments of this macro are the opening and closing strings respectively, followed by the arguments to be enclosed.

.Ql The quoted literal macro behaves differently in troff and nroff modes. If formatted with nroff(1), 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.

    The default width is 16n.

.Pf The prefix macro suppresses the whitespace between its first and second argument:

    .Pf ( Fa name2
        (name2

    The default width is 12n.

    The ‘.Ns’ macro (see below) performs the analogous suffix function.

.Ap The ‘.Ap’ macro inserts an apostrophe and exits any special text modes, continuing in ‘.No’ mode.

Examples of quoting:

.Aq <>
.Aq Pa ctype.h ) ,
    <ctype.h>),
.Bq []
.Bq Em Greek , French .
    [Greek, French].
.Dq “”
.Dq string abc .
    “string abc”.
.Dq '\[ha][A-Z]'
    “'^[A-Z]'”
.Ql man mdoc
    ‘man mdoc’
.Qq ""
.Qq string ) ,
    "string"),
.Qq string Ns ),
    "string),"
.Sq ‘’
.Sq string
    ‘string’
.Em or Ap ing
    or'ing

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 are discussed below.

  Normal text macro
‘’ formats subsequent argument(s) normally, ending the effect of ‘’ and similar. Parsing is not suppressed, so you must prefix words like ‘’ with ‘\&’ to avoid their interpretation as mdoc macros.

    Usage: .No argument ...

.Em Use caution No here .
    → Use caution here.
.Em No dogs allowed .
    → dogs allowed.
.Em \&No dogs allowed .
    → dogs allowed.

The default width is 12n.

  No-Space Macro
The ‘.Ns’ macro suppresses insertion of a space between the current position and its first parameter. For example, it is useful for old style argument lists where there is no space between the flag and argument:

    Usage: ... <argument>[<argument>] ...
           .Ns <argument> ...

.Op Fl I Ns Ar directory
    [-Idirectory]

Note: The ‘.Ns’ macro always invokes the ‘.No’ macro after eliminating the space unless another macro name follows it. If used as a command (i.e., the second form above in the ‘Usage’ line), ‘.Ns’ is identical to ‘.No’.

  (Sub)section cross references
Use the ‘.Sx’ macro to cite a (sub)section heading within the given document.

    Usage: .Sx <section-reference> ...

.Sx Files
    → Files

The default width is 16n.

  Symbolics
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 default width is 6n.

  Mathematical Symbols
Use this macro for mathematical symbols and similar things.

    Usage: .Ms <math symbol> ...

.Ms sigma
    → sigma

The default width is 6n.

  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(1) style references.

.Rs Reference start (does not take arguments). In a section titled “See also”, it causes a break and begins collection of reference information until the reference end macro is read.
.Re Reference end (does not take arguments). The reference is printed.
.%A Reference author name; one name per invocation.
.%B Book title.
.%C City/place.
.%D Date.
.%I Issuer/publisher name.
.%J Journal name.
.%N Issue number.
.%O Optional information.
.%P Page number.
.%Q Corporate or foreign author.
.%R Report name.
.%T Title of article.
.%U Optional hypertext reference.
.%V Volume.

Macros beginning with ‘%’ are not callable but accept multiple arguments in the usual way. Only the ‘.Tn’ macro is handled properly as a parameter; other macros will cause strange output. ‘.%B’ and ‘.%T’ can be used outside of the ‘.Rs/.Re’ environment.

Example:

    .Rs
    .%A "Matthew Bar"
    .%A "John Foo"
    .%T "Implementation Notes on foobar(1)"
    .%R "Technical Report ABC-DE-12-345"
    .%Q "Drofnats College"
    .%C "Nowhere"
    .%D "April 1991"
    .Re

produces

Matthew Bar, John Foo, Implementation Notes on foobar(1), Technical Report ABC-DE-12-345, Drofnats College, Nowhere, April 1991.

  Trade Names or Acronyms
The trade name macro prints its arguments at a smaller type size. It is intended to imitate a small caps fonts for fully capitalized acronyms.

    Usage: .Tn <symbol> ...

.Tn DEC
    DEC
.Tn ASCII
    ASCII

The default width is 10n.

  Extended Arguments
The .Xo and .Xc macros allow one to extend an argument list on a macro boundary for the ‘.It’ macro (see below). Note that .Xo and .Xc are implemented similarly to all other macros opening and closing an enclosure (without inserting characters, of course). This means that the following is true for those macros also.

Here is an example of ‘.Xo’ using the space mode macro to turn spacing off:

    .Bd -literal -offset indent
    .Sm off
    .It Xo Sy I Ar operation
    .No \en Ar count No \en
    .Xc
    .Sm on
    .Ed

produces

Ioperation
    \ncount\n

Another one:

    .Bd -literal -offset indent
    .Sm off
    .It Cm S No / Ar old_pattern Xo
    .No / Ar new_pattern
    .No / Op Cm g
    .Xc
    .Sm on
    .Ed

produces

S/old_pattern
    /new_pattern /[g]

Another example of ‘.Xo’ and enclosure macros: Test the value of a variable.

    .Bd -literal -offset indent
    .It Xo
    .Ic .ifndef
    .Oo \&! Oc Ns Ar variable Oo
    .Ar operator variable No ...
    .Oc Xc
    .Ed

produces

    .ifndef [!]variable [ operator variable ...]

Page structure domain

  Section headings
The following ‘.Sh’ section heading macros are required in every man page. The remaining section headings are recommended at the discretion of the author writing the manual page. The ‘.Sh’ macro is parsed but not generally callable. It can be used as an argument in a call to ‘.Sh’ only; it then reactivates the default font for ‘.Sh’.

The default width is 8n.

.Sh Name
    The ‘.Sh Name’ macro is mandatory. If not specified, 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.

    ‘.Nd’ first prints ‘-’, then all its arguments.

.Sh Library
    This section is for section two and three function calls. It should consist of a single ‘.Lb’ macro call; see Library Names.

.Sh Synopsis
    The Synopsis section describes the typical usage of the subject of a man page. The macros required are either ‘.Nm’, ‘.Cd’, or ‘.Fn’ (and possibly ‘.Fo’, ‘.Fc’, ‘.Fd’, and ‘.Ft’). 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, and 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 file No ...

.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).

.Sh Implementation notes
    Implementation specific information should be placed here.

.Sh Return values
    Sections 2, 3 and 9 function return values should go here. The ‘.Rv’ macro may be used to generate text for use in the Return values section for most section 2 and 3 library functions; see Return Values.

The following ‘.Sh’ section headings 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 Files
    Files which are used or created by the man page subject should be listed via the ‘.Pa’ macro in the Files section.

.Sh Examples
    There are several ways to create examples. See subsection Examples and Displays below for details.

.Sh Diagnostics
    Diagnostic messages from a command should be placed in this section. The ‘.Ex’ macro may be used to generate text for use in the Diagnostics section for most section 1, 6 and 8 commands; see Exit Status.

.Sh Compatibility
    Known compatibility issues (e.g. deprecated options or parameters) should be listed here.

.Sh Errors
    Specific error handling, especially from library functions (man page sections 2, 3, and 9) should go here. The ‘.Er’ macro is used to specify an error (errno).

.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. Currently refer(1) style references are not accommodated.

    It is recommended that the cross references be sorted by section number, then alphabetically by name within each section, then separated by commas. Example:

    ls(1), ps(1), group(5), passwd(5)

.Sh Standards
    If the command, library function, or file adheres to a specific implementation such as p1003.2 or ansiC 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 should be placed here. Use the ‘.An’ macro for names and the ‘.Aq’ macro for email addresses within optional contact information. Explicitly indicate whether the person authored the initial manual page or the software or whatever the person is being credited for.

.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"

  Subsection headings
Subsection headings have exactly the same syntax as section headings: ‘.Ss’ is parsed but not generally callable. It can be used as an argument in a call to ‘.Ss’ only; it then reactivates the default font for ‘.Ss’.

The default width is 8n.

  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’ or ‘.Bd’ macro (which both assert a vertical distance unless the -compact flag is given).

    The macro is neither callable nor parsed and takes no arguments; an alternative name is ‘.Lp’.

  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’ currently accepts is -words (also the default); this prevents breaks in the middle of options. In the example for make command-line arguments (see What's in a Name), the keep prevents nroff from placing the flag and the argument on separate lines.

Neither macro is callable or parsed.

More work needs to be done on the keep macros; specifically, a -line option should be added.

  Examples and Displays
There are seven types of displays.

.D1 (This is D-one.) Display one line of indented text. This macro is parsed but not callable.

        -ldghfstru

    The above was produced by: .D1 Fl ldghfstru.

.Dl (This is D-ell.) Display one line of indented literal text. The ‘.Dl’ example macro has been used throughout this file. It allows the indentation (display) of one line of text. Its default font is set to constant width (literal). ‘.Dl’ is parsed but not callable.

        % 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. It has the following syntax:

    .Bd {-literal | -filled | -unfilled | -ragged | -centered} [-offset <string>] [-file <file name>] [-compact]

    -ragged
        Fill, but do not adjust the right margin (only left-justify).
    -centered
        Center lines between the current left and right margin. Note that each single line is centered.
    -unfilled
        Do not fill; break lines where their input lines are broken. This can produce overlong lines without warning messages.
    -filled
        Display a filled block. The block of text is formatted (i.e., the text is justified on both the left and right side).
    -literal
        Display block with literal font (usually fixed-width). Useful for source code or simple tabbed or spaced text.
    -file <file name>
        The file whose name follows the -file flag is read and displayed before any data enclosed with ‘.Bd’ and ‘.Ed’, using the selected display type. Any troff/mdoc commands in the 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
            Indent by one default indent value or tab. The default indent value is also used for the ‘.D1’ and ‘.Dl’ macros, so one is guaranteed the two types of displays will line up. The indentation value is normally set to 6n or about two thirds of an inch (six constant width characters).
        indent-two
            Indent 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 within troff.

        If <string> is a valid numeric expression instead (with a scaling indicator other than ‘u’), use that value for indentation. The most useful scaling indicators are ‘m’ and ‘n’, specifying the so-called and En square. This is approximately the width of the letters ‘m’ and ‘n’ respectively of the current font (for nroff output, both scaling indicators give the same values). If <string> isn't a numeric expression, it is tested whether it is an mdoc macro name, and the default offset value associated with this macro is used. Finally, if all tests fail, the width of <string> (typeset with a fixed-width font) is taken as the offset.
    -compact
        Suppress insertion of vertical space before begin of display.

.Ed End display (takes no arguments).

  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. The use of columns inside of lists or lists inside of columns is untested.

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).

It has the following syntax forms:

.Bl {-hang | -ohang | -tag | -diag | -inset} [-width <string>] [-offset <string>] [-compact]
.Bl -column [-offset <string>] <string1> <string2> ...
.Bl {-item | -enum [-nested] | -bullet | -hyphen | -dash} [-offset <string>] [-compact]

And now a detailed description of the list types.

-bullet
    A bullet list.

        .Bl -bullet -offset indent -compact
        .It
        Bullet one goes here.
        .It
        Bullet two here.
        .El

    Produces:

    •   Bullet one goes here.
    •   Bullet two here.

-dash (or -hyphen)
    A dash list.

        .Bl -dash -offset indent -compact
        .It
        Dash one goes here.
        .It
        Dash two here.
        .El

    Produces:

    -   Dash one goes here.
    -   Dash two here.

-enum
    An enumerated list.

        .Bl -enum -offset indent -compact
        .It
        Item one goes here.
        .It
        And item two here.
        .El

    The result:

    1.  Item one goes here.
    2.  And item two here.

    If you want to nest enumerated lists, use the -nested flag (starting with the second-level list):

        .Bl -enum -offset indent -compact
        .It
        Item one goes here
        .Bl -enum -nested -compact
        .It
        Item two goes here.
        .It
        And item three here.
        .El
        .It
        And item four here.
        .El

    Result:

    1.  Item one goes here.
        1.  Item two goes here.
        2.  And item three here.
    2.  And item four here.

-item
    A list of type -item without list markers.

        .Bl -item -offset indent
        .It
        Item one goes here.
        Item one goes here.
        Item one goes here.
        .It
        Item two here.
        Item two here.
        Item two here.
        .El

    Produces:

    Item one goes here. Item one goes here. Item one goes here.

    Item two here. Item two here. Item two here.

-tag
    A list with tags. Use -width to specify the tag width.

    SL  sleep time of the process (seconds blocked)
    PAGEIN
        number of disk I/O operations 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 priority (non-positive when in non-interruptible wait)

    The raw text:

        .Bl -tag -width "PPID" -compact -offset indent
        .It SL
        sleep time of the process (seconds blocked)
        .It PAGEIN
        number of disk I/O operations 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 priority
        (non-positive when in non-interruptible wait)
        .El

-diag
    Diag lists create section four diagnostic lists and are similar to inset lists except callable macros are ignored. The -width flag is not meaningful in this context.

    Example:

        .Bl -diag
        .It You can't use Sy here.
        The message says all.
        .El

    produces

    You can't use here. The message says all.

-hang
    A list with hanging tags.

    Hanged
        labels appear similar to tagged lists when the label is smaller than the label width.

    Longer hanged list labels
        blend into 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 into the paragraph unlike
        tagged paragraph labels.
        .El

-ohang
    Lists with overhanging tags do not use indentation for the items; tags are written to a separate line.

    SL
    sleep time of the process (seconds blocked)

    PAGEIN
    number of disk I/O operations 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 priority (non-positive when in non-interruptible wait)

    The raw text:

        .Bl -ohang -offset indent
        .It Sy SL
        sleep time of the process (seconds blocked)
        .It Sy PAGEIN
        number of disk I/O operations resulting from references
        by the process to pages not loaded in core.
        .It Sy UID
        numerical user-id of process owner
        .It Sy PPID
        numerical id of parent of process priority
        (non-positive when in non-interruptible wait)
        .El

-inset
    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. Use a -width attribute as described below.

    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
        .Xr mdoc
        manuals to other formats.
        .El

-column
    This list type generates multiple columns. The number of columns and the width of each column is determined by the arguments to the -column list, <string1>, <string2>, etc. If <stringN> starts with a ‘’. (dot) immediately followed by a valid mdoc macro name, interpret <stringN> and use the width of the result. Otherwise, the width of <stringN> (typeset with a fixed-width font) is taken as the Nth column width.

    Each ‘.It’ argument is parsed to make a row, each column within the row is a separate argument separated by a tab or the ‘.Ta’ macro.

    The table:
    String | Nroff | Troff
    <= | <= |
    >= | >= |

    was produced by:

        .Bl -column -offset indent ".Sy String" ".Sy Nroff" ".Sy Troff"
        .It Sy String Ta Sy Nroff Ta Sy Troff
        .It Li <= Ta <= Ta \*(<=
        .It Li >= Ta >= Ta \*(>=
        .El

    Don't abuse this list type! For more complicated cases it might be far better and easier to use tbl(1), the table preprocessor.

Other keywords:

-width <string>
    If <string> starts with a ‘’. (dot) immediately followed by a valid mdoc macro name, interpret <string> and use the width of the result. Almost all lists in this document use this option.

    Example:

        .Bl -tag -width ".Fl test Ao Ar string Ac"
        .It Fl test Ao Ar string Ac
        This is a longer sentence to show how the
        .Fl width
        flag works in combination with a tag list.
        .El

    gives:

    -test <string>
        This is a longer sentence to show how the -width flag works in combination with a tag list.

    (Note that the current state of mdoc is saved before <string> is interpreted; afterwards, all variables are restored again. However, boxes (used for enclosures) can't be saved in GNU troff(1); as a consequence, arguments must always be balanced to avoid nasty errors. For example, do not write ‘.Ao Ar string’ but ‘.Ao Ar string Xc’ instead if you really need only an opening angle bracket.)

    Otherwise, if <string> is a valid numeric expression (with a scaling indicator other than ‘u’), use that value for indentation. The most useful scaling indicators are ‘m’ and ‘n’, specifying the so-called and En square. This is approximately the width of the letters ‘m’ and ‘n’ respectively of the current font (for nroff output, both scaling indicators give the same values). If <string> isn't a numeric expression, it is tested whether it is an mdoc macro name, and the default width value associated with this macro is used. Finally, if all tests fail, the width of <string> (typeset with a fixed-width font) is taken as the width.

    If a width is not specified for the tag list type, ‘6n’ is used.

-offset <string>
    If <string> is indent, a default indent value (normally set to 6n, similar to the value used in ‘.Dl’ or ‘.Bd’) is used. If <string> is a valid numeric expression instead (with a scaling indicator other than ‘u’), use that value for indentation. The most useful scaling indicators are ‘m’ and ‘n’, specifying the so-called and En square. This is approximately the width of the letters ‘m’ and ‘n’ respectively of the current font (for nroff output, both scaling indicators give the same values). If <string> isn't a numeric expression, it is tested whether it is an mdoc macro name, and the default offset value associated with this macro is used. Finally, if all tests fail, the width of <string> (typeset with a fixed-width font) is taken as the offset.

-compact
    Suppress insertion of vertical space before the list and between list items.

Miscellaneous macros
A double handful of macros fit only uncomfortably into one of the above sections. Of these, we couldn't find attested examples for ‘’ or ‘’. They are documented here for completeness—if you know their proper usage, please send a mail to groff@gnu.org and include a specimen with its provenance.

.Bt formats boilerplate text.

    .Bt →

    It is neither callable nor parsed and takes no arguments. Its default width is 6n.

.Fr is an obsolete means of specifying a function return value.

        Usage: .return-value ...

    ‘’ allows a break right before the return value (usually a single digit) which is bad typographical behaviour. Instead, set the return value with the rest of the code, using ‘\~’ to tie the return value to the previous word.

    Its default width is 12n.

.Hf Inlines the contents of a (header) file into the document.

        Usage: .Hf file

    It first prints ‘File:’ followed by the file name, then the contents of file. It is neither callable nor parsed.

.Lk Embed hyperlink.

        Usage: .uri [link-text]

    Its default width is 6n.

.Me Usage unknown. The mdoc sources describe it as a macro for “menu entries”.

    Its default width is 6n.

.Mt Embed email address.

        Usage: .~ email-address

    Its default width is 6n.

.Ot Usage unknown. The mdoc sources describe it as “old function type (fortran)”.

.Sm Manipulate or toggle argument-spacing mode.

        Usage: .Sm [on | off] ...

    If argument-spacing mode is off, no spaces between macro arguments are inserted. If called without a parameter (or if the next parameter is neither ‘on’ nor ‘off’), ‘Sm’ toggles argument-spacing mode.

    Its default width is 8n.

.Ud formats boilerplate text.

    .Ud →

    It is neither callable nor parsed and takes no arguments. Its default width is 8n.

Predefined strings
The following strings are predefined for compatibility with legacy mdoc documents. Contemporary ones should use the alternatives shown in the “Prefer” column below. See groff_char(7) for a full discussion of these special character escape sequences.

String | 7-bit | 8-bit | UCS | Prefer | Meaning
\*(<= | <= | <= |  | \(<= | less than or equal to
\*(>= | >= | >= |  | \(>= | greater than or equal to
\*(Rq | " | " |  | \(rq | right double quote
\*(Lq | " | " |  | \(lq | left double quote
\*(ua | ^ | ^ |  | \(ua | vertical arrow up
\*(aa | ' | ' |  | \(aa | acute accent
\*(ga | ` | ` |  | \(ga | grave accent
\*(q | " | " |  | \(dq | neutral double quote
\*(Pi | pi | pi |  | \(*p | lowercase pi
\*(Ne | != | != |  | \(!= | not equals
\*(Le | <= | <= |  | \(<= | less than or equal to
\*(Ge | >= | >= |  | \(>= | greater than or equal to
\*(Lt | < | < |  | < | less than
\*(Gt | > | > |  | > | greater than
\*(Pm | +- | ± |  | \(+- | plus or minus
\*(If | infinity | infinity |  | \(if | infinity
\*(Am |  |  |  | & | ampersand
\*(Na |  |  |  | NaN | not a number
\*(Ba |  |  |  | | | bar

Some column headings are shorthand for standardized character encodings; “7-bit” for ISO 646:1991 IRV (US-ASCII), “8-bit” for ISO 8859-1 (Latin-1) and IBM code page 1047, and “UCS” for ISO 10646 (Unicode character set). Historically, mdoc configured the string definitions to fit the capabilities expected of the output device. Old typesetters lacked directional double quotes, producing repeated directional single quotes ‘‘like this’’; early versions of mdoc in fact defined the ‘Lq’ and ‘Rq’ strings this way. Nowadays, output drivers take on the responsibility of glyph substitution, as they possess relevant knowledge of their available repertoires.

Diagnostics
The debugging macro ‘.Db’ offered by previous versions of mdoc is unavailable in GNU troff(1) since the latter provides better facilities to check parameters; additionally, groff mdoc implements many error and warning messages, making the package more robust and more verbose.

The remaining debugging macro is ‘.Rd’, which dumps the package's global register and string contents to the standard error stream. A normal user will never need it.

Options
The following groff options set registers (with -r) and strings (with -d) recognized and used by the mdoc macro package. To ensure rendering consistent with output device capabilities and reader preferences, man pages should never manipulate them.

Setting string ‘AD’ configures the adjustment mode for most formatted text. Typical values are ‘b’ for adjustment to both margins (the default), or ‘l’ for left alignment (ragged right margin). Any valid argument to groff's ‘ad’ request may be used. See groff(7) for less-common choices.
    groff -Tutf8 -dAD=l -mdoc groff_mdoc.7 | less -R

Setting register ‘C’ to 1 numbers output pages consecutively, rather than resetting the page number to 1 (or the value of register ‘P’) with each new mdoc document.

By default, the package inhibits page breaks, headers, and footers in the midst of the document text if it is being displayed with a terminal device such as ‘latin1’ or ‘utf8’, to enable more efficient viewing of the page. This behavior can be changed to format the page as if for 66-line Teletype output by setting the continuous rendering register ‘cR’ to zero while calling groff(1).
    groff -Tlatin1 -rcR=0 -mdoc foo.man > foo.txt
On HTML devices, it cannot be disabled.

Section headings (defined with ‘.Sh’) and page titles in headers (defined with ‘.Dt’) can be presented in full capitals by setting the registers ‘CS’ and ‘CT’, respectively, to 1. These transformations are off by default because they discard case distinction information.

Setting register ‘D’ to 1 enables double-sided page layout, which is only distinct when not continuously rendering. It places the page number at the bottom right on odd-numbered (recto) pages, and at the bottom left on even-numbered (verso) pages, swapping places with the arguments to ‘.Os’.
    groff -Tps -rD1 -mdoc foo.man > foo.ps

The value of the ‘FT’ register determines the footer's distance from the page bottom; this amount is always negative and should specify a scaling unit. At one half-inch above this location, the page text is broken before writing the footer. It is ignored if continuous rendering is enabled. The default is -0.5i.

The ‘HF’ string sets the font used for section and subsection headings; the default is ‘B’ (bold style of the default family). Any valid argument to groff's ‘ft’ request may be used.

Normally, automatic hyphenation is enabled using a mode appropriate to the groff locale; see section “Localization“ of groff(7). It can be disabled by setting the ‘HY’ register to zero.
    groff -Tutf8 -rHY=0 -mdoc foo.man | less -R

The paragraph and subsection heading indentation amounts can be changed by setting the registers ‘IN’ and ‘SN’.
    groff -Tutf8 -rIN=5n -rSN=2n -mdoc foo.man | less -R
The default paragraph indentation is 7.2n on typesetters and 7n on terminals. The default subsection heading indentation amount is 3n; section headings are set with an indentation of zero.

The line and title lengths can be changed by setting the registers ‘LL’ and ‘LT’, respectively:
    groff -Tutf8 -rLL=100n -rLT=100n -mdoc foo.man | less -R
If not set, both registers default to 78n for terminal devices and 6.5i otherwise.

Setting the ‘P’ register starts enumeration of pages at its value. The default is 1.

To change the document font size to 11p or 12p, set register ‘S’ accordingly:
    groff -Tdvi -rS11 -mdoc foo.man > foo.dvi
Register ‘S’ is ignored when formatting for terminal devices.

Setting the ‘X’ register to a page number p numbers its successors as pa, pb, pc, and so forth. The register tracking the suffixed page letter uses format ‘a’ (see the ‘af’ request in groff(7)).

Files

/usr/share/groff/1.23.0/tmac/andoc.tmac
    This brief groff program detects whether the man or mdoc macro package is being used by a document and loads the correct macro definitions, taking advantage of the fact that pages using them must call TH or Dd, respectively, before any other macros. A user typing, for example,
        groff -mandoc page.1
    need not know which package the file page.1 uses. Multiple man pages, in either format, can be handled; andoc.tmac reloads each macro package as necessary.

/usr/share/groff/1.23.0/tmac/doc.tmac
    implements the bulk of the groff mdoc package and loads further components as needed from the mdoc subdirectory.

/usr/share/groff/1.23.0/tmac/mdoc.tmac
    is a wrapper that loads doc.tmac.

/usr/share/groff/1.23.0/tmac/mdoc/doc-common
    defines macros, registers, and strings concerned with the production of formatted output. It includes strings of the form ‘doc-volume-ds-X’ and ‘doc-volume-as-X’ for manual section titles and architecture identifiers, respectively, where X is an argument recognized by .Dt.

/usr/share/groff/1.23.0/tmac/mdoc/doc-nroff
    defines parameters appropriate for rendering to terminal devices.

/usr/share/groff/1.23.0/tmac/mdoc/doc-ditroff
    defines parameters appropriate for rendering to typesetter devices.

/usr/share/groff/1.23.0/tmac/mdoc/doc-syms
    defines many strings and macros that interpolate formatted text, such as names of operating system releases, *BSD libraries, and standards documents. The string names are of the form ‘doc-str-O-V’, ‘doc-str-St--S-I’ (observe the double dashes), or ‘doc-str-Lb-L’, where O is one of the operating system macros from section General text domain above, V is an encoding of an operating system release (sometimes omitted along with the ‘-’ preceding it), S an identifier for a standards body or committee, I one for an issue of a standard promulgated by S, and L a keyword identifying a *BSD library.

/usr/share/groff/site-tmac/mdoc.local
    This file houses local additions and customizations to the package. It can be empty.

See also
The mandoc: https://mandoc.bsd.lv/ project maintains an independent implementation of the mdoc language and a renderer that directly parses its markup as well as that of man.

groff(1), man(1), troff(1), groff_man(7), mdoc(7)

Bugs
Section 3f has not been added to the header routines.

‘.Fn’ needs to have a check to prevent splitting up the line if its length is too short. Occasionally it separates the last parenthesis, and sometimes looks ridiculous if output lines are being filled.

The list and display macros do not do any keeps and certainly should be able to.

As of groff 1.23, ‘’ no longer changes the type size; this functionality may return in the next release.