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.\"     $Id: man.7,v 1.34 2009/08/20 13:51:55 kristaps Exp $
.\"
.\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@kth.se>
.\"
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.Dd $Mdocdate: August 20 2009 $
.Dt MAN 7
.Os
.
.
.Sh NAME
.Nm man
.Nd man language reference
.
.
.Sh DESCRIPTION
The
.Nm man
language was historically used to format
.Ux
manuals.  This reference document describes its syntax, structure, and
usage.
.
.Pp
.Bf -emphasis
Do not use
.Nm
to write your manuals.
.Ef
Use the
.Xr mdoc 7
language, instead.
.
.Pp
An
.Nm
document follows simple rules:  lines beginning with the control
character
.Sq \&.
are parsed for macros.  Other lines are interpreted within the scope of
prior macros:
.Bd -literal -offset indent
\&.SH Macro lines change control state.
Other lines are interpreted within the current state.
.Ed
.
.
.Sh INPUT ENCODING
.Nm
documents may contain only graphable 7-bit ASCII characters, the
space character, and the tabs character.  All manuals must have
.Ux
line termination.
.
.Pp
Blank lines are acceptable; where found, the output will assert a
vertical space.
.
.Pp
The
.Sq \ec
escape is common in historical
.Nm
documents; if encountered at the end of a word, it ensures that the
subsequent word isn't off-set by whitespace.
.
.
.Ss Comments
Text following a
.Sq \e\*" ,
whether in a macro or free-form text line, is ignored to the end of
line.  A macro line with only a control character and comment escape,
.Sq \&.\e" ,
is also ignored.  Macro lines with only a control charater and
optionally whitespace are stripped from input.
.
.
.Ss Special Characters
Special characters may occur in both macro and free-form lines.
Sequences begin with the escape character
.Sq \e
followed by either an open-parenthesis
.Sq \&(
for two-character sequences; an open-bracket
.Sq \&[
for n-character sequences (terminated at a close-bracket
.Sq \&] ) ;
or a single one-character sequence.  See
.Xr mandoc_char 7
for a complete list.  Examples include
.Sq \e(em
.Pq em-dash
and
.Sq \ee
.Pq back-slash .
.
.
.Ss Text Decoration
Terms may be text-decorated using the
.Sq \ef
escape followed by an indicator: B (bold), I, (italic), or P and R
(Roman, or reset).
.
.
.Ss Whitespace
Unless specifically escaped, consecutive blocks of whitespace are pruned
from input.  These are later re-added, if applicable, by a front-end
utility such as
.Xr mandoc 1 .
.
.
.Sh MANUAL STRUCTURE
Each
.Nm
document must contain contains at least the
.Sq TH
macro describing the document's section and title.  It may occur
anywhere in the document, although conventionally, it appears as the
first macro.
.
.Pp
Beyond
.Sq TH ,
at least one macro or text node must appear in the document.  Documents
are generally structured as follows:
.Bd -literal -offset indent
\&.TH FOO 1 "13 Aug 2009"
\&.
\&.SH NAME
\efBfoo\efR \e(en a description goes here
\&.\e\*q The next is for sections 2 & 3 only.
\&.\e\*q .SH LIBRARY
\&.
\&.SH SYNOPSIS
\efBfoo\efR [\efB\e-options\efR] arguments...
\&.
\&.SH DESCRIPTION
The \efBfoo\efR utility processes files...
\&.
\&.\e\*q .SH IMPLEMENTATION NOTES
\&.\e\*q The next is for sections 1 & 8 only.
\&.\e\*q .SH EXIT STATUS
\&.\e\*q The next is for sections 2, 3, & 9 only.
\&.\e\*q .SH RETURN VALUES
\&.\e\*q The next is for sections 1, 6, 7, & 8 only.
\&.\e\*q .SH ENVIRONMENT
\&.\e\*q .SH FILES
\&.\e\*q .SH EXAMPLES
\&.\e\*q The next is for sections 1, 4, 6, 7, & 8 only.
\&.\e\*q .SH DIAGNOSTICS
\&.\e\*q The next is for sections 2, 3, & 9 only.
\&.\e\*q .SH ERRORS
\&.\e\*q .SH SEE ALSO
\&.\e\*q \efBbar\efR(1)
\&.\e\*q .SH STANDARDS
\&.\e\*q .SH HISTORY
\&.\e\*q .SH AUTHORS
\&.\e\*q .SH CAVEATS
\&.\e\*q .SH BUGS
\&.\e\*q .SH SECURITY CONSIDERATIONS
.Ed
.
.
.Sh MACRO SYNTAX
Macros are one to three three characters in length and begin with a
control character ,
.Sq \&. ,
at the beginning of the line.  An arbitrary amount of whitespace may
sit between the control character and the macro name.  Thus,
.Sq .PP
and
.Sq \&.\ \ \ PP
are equivalent.
.
.Pp
The
.Nm
macros are classified by scope: line scope or block scope.  Line
macros are only scoped to the current line (and, in some situations,
the subsequent line).  Block macros are scoped to the current line and
subsequent lines until closed by another block macro.
.
.
.Ss Line Macros
Line macros are generally scoped to the current line, with the body
consisting of zero or more arguments.  If a macro is scoped to the next
line and the line arguments are empty, the next line is used instead,
else the general syntax is used.  Thus:
.Bd -literal -offset indent
\&.I
foo
.Ed
.
.Pp
is equivalent to
.Sq \&.I foo .
.\" PARAGRAPH
Consecutive next-line scope invocations are disallowed.
.Bd -literal -offset indent
\&.YO \(lBbody...\(rB
\(lBbody...\(rB
.Ed
.
.Pp
It is considered an error when next-line scope is open at the end of
file.
.
.Pp
.Bl -column -compact -offset indent "MacroX" "ArgumentsX" "ScopeXXXXX"
.It Em Macro Ta Em Arguments Ta Em Scope
.It    B     Ta    n         Ta    next-line
.It    BI    Ta    n         Ta    current
.It    BR    Ta    n         Ta    current
.It    DT    Ta    0         Ta    current
.It    I     Ta    n         Ta    next-line
.It    IB    Ta    n         Ta    current
.It    IR    Ta    n         Ta    current
.It    R     Ta    n         Ta    next-line
.It    RB    Ta    n         Ta    current
.It    RI    Ta    n         Ta    current
.It    SB    Ta    n         Ta    next-line
.It    SM    Ta    n         Ta    next-line
.It    TH    Ta    >1, <6    Ta    current
.It    br    Ta    0         Ta    current
.It    fi    Ta    0         Ta    current
.It    i     Ta    n         Ta    current
.It    na    Ta    0         Ta    current
.It    nf    Ta    0         Ta    current
.It    r     Ta    0         Ta    current
.It    sp    Ta    1         Ta    current
.El
.
.Pp
The
.Sq RS ,
.Sq RE ,
.Sq br ,
.Sq fi ,
.Sq i ,
.Sq na ,
.Sq nf ,
.Sq r ,
and
.Sq sp
macros aren't historically part of
.Nm
and should not be used.  They're included for compatibility.
.
.
.Ss Block Macros
Block macros are comprised of a head and body.  Like for in-line macros,
the head is scoped to the current line and, in one circumstance, the
next line; the body is scoped to subsequent lines and is closed out by a
subsequent block macro invocation.
.Bd -literal -offset indent
\&.YO \(lBhead...\(rB
\(lBhead...\(rB
\(lBbody...\(rB
.Ed
.
.Pp
The closure of body scope may be to the section, where a macro is closed
by
.Sq SH ;
sub-section, closed by a section or
.Sq SS ;
part, closed by a section, sub-section, or
.Sq RE ;
or paragraph, closed by a section, sub-section, part, 
.Sq HP ,
.Sq IP ,
.Sq LP ,
.Sq P ,
.Sq PP ,
or
.Sq TP .
No closure refers to an explicit block closing macro.
.
.Pp
It is considered an error when part or next-line scope is open at the
end of file.
.
.Pp
.Bl -column "MacroX" "ArgumentsX" "Head ScopeX" "sub-sectionX" -compact -offset indent
.It Em Macro Ta Em Arguments Ta Em Head Scope Ta Em Body Scope
.It   HP     Ta    <2        Ta    current    Ta    paragraph
.It   IP     Ta    <3        Ta    current    Ta    paragraph
.It   LP     Ta    0         Ta    current    Ta    paragraph
.It   P      Ta    0         Ta    current    Ta    paragraph
.It   PP     Ta    0         Ta    current    Ta    paragraph
.It   RE     Ta    0         Ta    current    Ta    none
.It   RS     Ta    1         Ta    current    Ta    part
.It   SH     Ta    >0        Ta    next-line  Ta    section
.It   SS     Ta    >0        Ta    next-line  Ta    sub-section
.It   TP     Ta    n         Ta    next-line  Ta    paragraph
.El
.
.Pp
If a block macro is next-line scoped, it may only be followed by in-line
macros (excluding
.Sq DT ,
.Sq TH ,
.Sq br ,
.Sq na ,
.Sq sp ,
.Sq nf ,
and
.Sq fi ) .
.
.
.Sh REFERENCE
This section is a canonical reference to all macros, arranged
alphabetically.  For the scoping of individual macros, see
.Sx MACRO SYNTAX .
.
.
.Ss Definitions
In this reference, a numerical width may be either a standalone natural
number (such as 3, 4, 10, etc.) or a natural number followed by a width
multiplier 
.Qq n ,
corresponding to the width of the formatted letter n, or
.Qq m ,
corresponding to the width of the formatted letter m.  The latter is the
default, if unspecified.  Thus,
.Bd -literal -offset indent
\&.HP 12n
.Ed
.
.Pp
indicates an offset of 12 
.Qq n
.Ns -sized
letters.
.
.
.Ss Macro Reference
.Bl -tag -width Ds
.It B
Text is rendered in bold face.
.It BI
Text is rendered alternately in bold face and italic.  Thus, 
.Sq .BI this word and that
causes
.Sq this
and
.Sq and
to render in bold face, while 
.Sq word
and
.Sq that
render in italics.  Whitespace between arguments is omitted in output.
.It BR
Text is rendered alternately in bold face and roman (the default font).
Whitespace between arguments is omitted in output.
.It DT
Re-set the tab spacing to 0.5 inches.
.It HP
Begin a paragraph whose initial output line is left-justified, but
subsequent output lines are indented, with the following syntax:
.Bd -literal -offset indent
\&.HP [width]
.Ed
.
.Pp
If 
.Va width
is specified, it's saved for later paragraph left-margins; if
unspecified, the saved or default width is used.
.It I
Text is rendered in italics.
.It IB
Text is rendered alternately in italics and bold face.  Whitespace
between arguments is omitted in output.
.It IP
Begin a paragraph with the following syntax:
.Bd -literal -offset indent
\&.IP [head [width]]
.Ed
.
.Pp
This follows the behaviour of the
.Sq TP
except for the macro syntax (all arguments on the line, instead of
having next-line scope).  If
.Va width
is specified, it's saved for later paragraph left-margins; if
unspecified, the saved or default width is used.
.It IR
Text is rendered alternately in italics and roman (the default font).
Whitespace between arguments is omitted in output.
.It LP, P, PP
Begin an undecorated paragraph.  The scope of a paragraph is closed by a
subsequent paragraph, sub-section, section, or end of file.  The saved
paragraph left-margin width is re-set to the default.
.It R
Text is rendered in roman (the default font).
.It RB
Text is rendered alternately in roman (the default font) and bold face.
Whitespace between arguments is omitted in output.
.It RE
Explicitly close out the scope of a prior
.Sq RS .
.It RI
Text is rendered alternately in roman (the default font) and italics.
Whitespace between arguments is omitted in output.
.It RS
Begin a part setting the left margin.  The left margin controls the
offset, following an initial indentation, to un-indented text such as
that of
.Sq PP .
The width may be specified as following:
.Bd -literal -offset indent
\&.RS [width]
.Ed
.
.Pp
If
.Va width
is not specified, the saved or default width is used. 
.It SB
Text is rendered in small size (one point smaller than the default font)
bold face.
.It SH
Begin a section.  The scope of a section is only closed by another
section or the end of file.  The paragraph left-margin width is re-set
to the default.
.It SM
Text is rendered in small size (one point smaller than the default
font).
.It SS
Begin a sub-section.  The scope of a sub-section is closed by a
subsequent sub-section, section, or end of file.  The paragraph
left-margin width is re-set to the default.
.It TH
Sets the title of the manual page with the following syntax:
.Bd -literal -offset indent
\&.TH title section [date [source [volume]]]
.Ed
.
.Pp
At least the 
.Va title
and
.Va section
arguments must be provided.  The
.Va date
argument should be formatted as
.Qq %b [%d] %Y
format, described in
.Xr strptime 3 .
The
.Va source
string specifies the organisation providing the utility.  The
.Va volume
replaces the default rendered volume as dictated by the manual section.
.It TP
Begin a paragraph where the head, if exceeding the indentation width, is
followed by a newline; if not, the body follows on the same line after a
buffer to the indentation width.  Subsequent output lines are indented.
.
.Pp
The indentation width may be set as follows:
.Bd -literal -offset indent
\&.TP [width]
.Ed
.
.Pp
Where
.Va width
must be a properly-formed numeric width.  If
.Va width
is specified, it's saved for later paragraph left-margins; if
unspecified, the saved or default width is used.
.It br
Breaks the current line.  Consecutive invocations have no further effect.
.It fi
End literal mode begun by
.Sq nf .
.It i
Italicise arguments.  If no arguments are specified, all subsequent text
is italicised.
.It na
Don't alignment the right margin.
.It nf
Begin literal mode: all subsequent free-form lines have their end of
line boundaries preserved.  May be ended by
.Sq fi .
.It r
Fonts and styles (bold face, italics) reset to roman (default font).
.It sp
Insert n spaces, where n is the macro's positive numeric argument.  If
0, this is equivalent to the
.Sq br
macro.
.El
.
.
.Sh COMPATIBILITY
This section documents compatibility with other roff implementations, at
this time limited to
.Xr groff 1 .
.Bl -hyphen
.It
In quoted literals, groff allowed pair-wise double-quotes to produce a
standalone double-quote in formatted output.  This idiosyncratic
behaviour is no longer applicable.
.It
The
.Sq sp
macro does not accept negative numbers.
.It
Blocks of whitespace are stripped from both macro and free-form text
lines (except when in literal mode), while groff would retain whitespace
in free-form text lines.
.El
.
.
.Sh SEE ALSO
.Xr mandoc 1 ,
.Xr mandoc_char 7
.
.
.Sh AUTHORS
The
.Nm
reference was written by
.An Kristaps Dzonsons Aq kristaps@kth.se .
.
.
.Sh CAVEATS
Do not use this language.  Use
.Xr mdoc 7 ,
instead.
.