+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), R (Roman), or P
+(revert to previous mode):
+.Pp
+.Dl \efBbold\efR \efIitalic\efP
+.Pp
+A numerical representation 3, 2, or 1 (bold, italic, and Roman,
+respectively) may be used instead.
+If a macro opens a font scope after calling
+.Sq \ef ,
+such as with
+.Sx \&Bf ,
+the
+.Sq \ef
+mode will be restored upon exiting the
+.Sx \&Bf
+scope.
+.Pp
+Note this form is
+.Em not
+recommended for
+.Nm ,
+which encourages semantic annotation.
+.Ss Predefined Strings
+Historically,
+troff
+also defined a set of package-specific
+.Dq predefined strings ,
+which, like
+.Sx Special Characters ,
+mark special output characters and strings by way of input codes.
+Predefined strings are escaped with the slash-asterisk,
+.Sq \e* :
+single-character
+.Sq \e*X ,
+two-character
+.Sq \e*(XX ,
+and N-character
+.Sq \e*[N] .
+See
+.Xr mandoc_char 7
+for a complete list.
+Examples include
+.Sq \e*(Am
+.Pq ampersand
+and
+.Sq \e*(Ba
+.Pq vertical bar .
+.Ss Whitespace
+Whitespace consists of the space character.
+In text lines, whitespace is preserved within a line; unescaped
+trailing spaces are stripped from input (unless in a literal context).
+Blank text lines, which may include whitespace, are only permitted
+within literal contexts.
+.Pp
+In macro lines, whitespace delimits arguments and is discarded.
+If arguments are quoted, whitespace within the quotes is retained.
+.Ss Quotation
+Macro arguments may be quoted with double-quotes to group
+space-delimited terms or to retain blocks of whitespace.
+A quoted argument begins with a double-quote preceded by whitespace.
+The next double-quote not pairwise adjacent to another double-quote
+terminates the literal, regardless of surrounding whitespace.
+.Pp
+Note that any quoted text, even if it would cause a macro invocation
+when unquoted, is considered literal text.
+Thus, the following produces
+.Sq Op "Fl a" :
+.Bd -literal -offset indent
+\&.Op "Fl a"
+.Ed
+.Pp
+In text lines, quotes are regarded as opaque text.
+.Ss Scaling Widths
+Many macros support scaled widths for their arguments, such as
+stipulating a two-inch list indentation with the following:
+.Bd -literal -offset indent
+\&.Bl -tag -width 2i
+.Ed
+.Pp
+The syntax for scaled widths is
+.Sq Li [+-]?[0-9]*.[0-9]*[:unit:] ,
+where a decimal must be preceded or proceeded by at least one digit.
+Negative numbers, while accepted, are truncated to zero.
+The following scaling units are accepted:
+.Pp
+.Bl -tag -width Ds -offset indent -compact
+.It c
+centimetre
+.It i
+inch
+.It P
+pica (~1/6 inch)
+.It p
+point (~1/72 inch)
+.It f
+synonym for
+.Sq u
+.It v
+default vertical span
+.It m
+width of rendered
+.Sq m
+.Pq em
+character
+.It n
+width of rendered
+.Sq n
+.Pq en
+character
+.It u
+default horizontal span
+.It M
+mini-em (~1/100 em)
+.El
+.Pp
+Using anything other than
+.Sq m ,
+.Sq n ,
+.Sq u ,
+or
+.Sq v
+is necessarily non-portable across output media.
+See
+.Sx COMPATIBILITY .
+.Ss Sentence Spacing
+When composing a manual, make sure that sentences end at the end of
+a line.
+By doing so, front-ends will be able to apply the proper amount of
+spacing after the end of sentence (unescaped) period, exclamation mark,
+or question mark followed by zero or more non-sentence closing
+delimiters
+.Po
+.Sq \&) ,
+.Sq \&] ,
+.Sq \&' ,
+.Sq \&"
+.Pc .
+.Pp
+The proper spacing is also intelligently preserved if a sentence ends at
+the boundary of a macro line.
+For example:
+.Pp
+.Dl \&.Xr mandoc 1 \&.
+.Dl \&.Fl T \&Ns \&Cm ascii \&.
+.Sh MANUAL STRUCTURE
+A well-formed
+.Nm
+document consists of a document prologue followed by one or more
+sections.
+.Pp
+The prologue, which consists of the
+.Sx \&Dd ,
+.Sx \&Dt ,
+and
+.Sx \&Os
+macros in that order, is required for every document.
+.Pp
+The first section (sections are denoted by
+.Sx \&Sh )
+must be the NAME section, consisting of at least one
+.Sx \&Nm
+followed by
+.Sx \&Nd .
+.Pp
+Following that, convention dictates specifying at least the
+.Em SYNOPSIS
+and
+.Em DESCRIPTION
+sections, although this varies between manual sections.
+.Pp
+The following is a well-formed skeleton
+.Nm
+file:
+.Bd -literal -offset indent
+\&.Dd $\&Mdocdate$
+\&.Dt mdoc 7
+\&.Os
+\&.Sh NAME
+\&.Nm foo
+\&.Nd a description goes here
+\&.\e\*q .Sh LIBRARY
+\&.\e\*q For sections 2, 3, & 9 only.
+\&.\e\*q Not used in OpenBSD.
+\&.Sh SYNOPSIS
+\&.Nm foo
+\&.Op Fl options
+\&.Ar
+\&.Sh DESCRIPTION
+The
+\&.Nm
+utility processes files ...
+\&.\e\*q .Sh IMPLEMENTATION NOTES
+\&.\e\*q Not used in OpenBSD.
+\&.\e\*q .Sh RETURN VALUES
+\&.\e\*q For sections 2, 3, & 9 only.
+\&.\e\*q .Sh ENVIRONMENT
+\&.\e\*q For sections 1, 6, 7, & 8 only.
+\&.\e\*q .Sh FILES
+\&.\e\*q .Sh EXIT STATUS
+\&.\e\*q For sections 1, 6, & 8 only.
+\&.\e\*q .Sh EXAMPLES
+\&.\e\*q .Sh DIAGNOSTICS
+\&.\e\*q For sections 1, 4, 6, 7, & 8 only.
+\&.\e\*q .Sh ERRORS
+\&.\e\*q For sections 2, 3, & 9 only.
+\&.\e\*q .Sh SEE ALSO
+\&.\e\*q .Xr foobar 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
+\&.\e\*q Not used in OpenBSD.
+.Ed
+.Pp
+The sections in an
+.Nm
+document are conventionally ordered as they appear above.
+Sections should be composed as follows:
+.Bl -ohang -offset Ds
+.It Em NAME
+The name(s) and a one line description of the documented material.
+The syntax for this as follows:
+.Bd -literal -offset indent
+\&.Nm name0 ,
+\&.Nm name1 ,
+\&.Nm name2
+\&.Nd a one line description
+.Ed
+.Pp
+Multiple
+.Sq \&Nm
+names should be separated by commas.
+.Pp
+The
+.Sx \&Nm
+macro(s) must precede the
+.Sx \&Nd
+macro.
+.Pp
+See
+.Sx \&Nm
+and
+.Sx \&Nd .
+.It Em LIBRARY
+The name of the library containing the documented material, which is
+assumed to be a function in a section 2, 3, or 9 manual.
+The syntax for this is as follows:
+.Bd -literal -offset indent
+\&.Lb libarm
+.Ed
+.Pp
+See
+.Sx \&Lb .
+.It Em SYNOPSIS
+Documents the utility invocation syntax, function call syntax, or device
+configuration.
+.Pp
+For the first, utilities (sections 1, 6, and 8), this is
+generally structured as follows:
+.Bd -literal -offset indent
+\&.Nm bar
+\&.Op Fl v
+\&.Op Fl o Ar file
+\&.Op Ar
+\&.Nm foo
+\&.Op Fl v
+\&.Op Fl o Ar file
+\&.Op Ar
+.Ed
+.Pp
+Commands should be ordered alphabetically.
+.Pp
+For the second, function calls (sections 2, 3, 9):
+.Bd -literal -offset indent
+\&.In header.h
+\&.Vt extern const char *global;
+\&.Ft "char *"
+\&.Fn foo "const char *src"
+\&.Ft "char *"
+\&.Fn bar "const char *src"
+.Ed
+.Pp
+Ordering of
+.Sx \&In ,
+.Sx \&Vt ,
+.Sx \&Fn ,
+and
+.Sx \&Fo
+macros should follow C header-file conventions.
+.Pp
+And for the third, configurations (section 4):
+.Bd -literal -offset indent
+\&.Cd \*qit* at isa? port 0x2e\*q
+\&.Cd \*qit* at isa? port 0x4e\*q
+.Ed
+.Pp
+Manuals not in these sections generally don't need a
+.Em SYNOPSIS .
+.Pp
+Some macros are displayed differently in the
+.Em SYNOPSIS
+section, particularly
+.Sx \&Nm ,
+.Sx \&Cd ,
+.Sx \&Fd ,
+.Sx \&Fn ,
+.Sx \&Fo ,
+.Sx \&In ,
+.Sx \&Vt ,
+and
+.Sx \&Ft .
+All of these macros are output on their own line.
+If two such dissimilar macros are pairwise invoked (except for
+.Sx \&Ft
+before
+.Sx \&Fo
+or
+.Sx \&Fn ) ,
+they are separated by a vertical space, unless in the case of
+.Sx \&Fo ,
+.Sx \&Fn ,
+and
+.Sx \&Ft ,
+which are always separated by vertical space.
+.Pp
+When text and macros following an
+.Sx \&Nm
+macro starting an input line span multiple output lines,
+all output lines but the first will be indented to align
+with the text immediately following the
+.Sx \&Nm
+macro, up to the next
+.Sx \&Nm ,
+.Sx \&Sh ,
+or
+.Sx \&Ss
+macro or the end of an enclosing block, whichever comes first.
+.It Em DESCRIPTION
+This begins with an expansion of the brief, one line description in
+.Em NAME :
+.Bd -literal -offset indent
+The
+\&.Nm
+utility does this, that, and the other.
+.Ed
+.Pp
+It usually follows with a breakdown of the options (if documenting a
+command), such as:
+.Bd -literal -offset indent
+The arguments are as follows:
+\&.Bl \-tag \-width Ds
+\&.It Fl v
+Print verbose information.
+\&.El
+.Ed
+.Pp
+Manuals not documenting a command won't include the above fragment.
+.It Em IMPLEMENTATION NOTES
+Implementation-specific notes should be kept here.
+This is useful when implementing standard functions that may have side
+effects or notable algorithmic implications.
+.It Em RETURN VALUES
+This section documents the
+return values of functions in sections 2, 3, and 9.
+.Pp
+See
+.Sx \&Rv .
+.It Em ENVIRONMENT
+Lists the environment variables used by the utility,
+and explains the syntax and semantics of their values.
+The
+.Xr environ 7
+manual provides examples of typical content and formatting.
+.Pp
+See
+.Sx \&Ev .
+.It Em FILES
+Documents files used.
+It's helpful to document both the file name and a short description of how
+the file is used (created, modified, etc.).
+.Pp
+See
+.Sx \&Pa .
+.It Em EXIT STATUS
+This section documents the
+command exit status for section 1, 6, and 8 utilities.
+Historically, this information was described in
+.Em DIAGNOSTICS ,
+a practise that is now discouraged.
+.Pp
+See
+.Sx \&Ex .
+.It Em EXAMPLES
+Example usages.
+This often contains snippets of well-formed, well-tested invocations.
+Make sure that examples work properly!
+.It Em DIAGNOSTICS
+Documents error conditions.
+This is most useful in section 4 manuals.
+Historically, this section was used in place of
+.Em EXIT STATUS
+for manuals in sections 1, 6, and 8; however, this practise is
+discouraged.
+.Pp
+See
+.Sx \&Bl
+.Fl diag .
+.It Em ERRORS
+Documents error handling in sections 2, 3, and 9.
+.Pp
+See
+.Sx \&Er .
+.It Em SEE ALSO
+References other manuals with related topics.
+This section should exist for most manuals.
+Cross-references should conventionally be ordered first by section, then
+alphabetically.
+.Pp
+See
+.Sx \&Xr .
+.It Em STANDARDS
+References any standards implemented or used.
+If not adhering to any standards, the
+.Em HISTORY
+section should be used instead.
+.Pp
+See
+.Sx \&St .
+.It Em HISTORY
+A brief history of the subject, including where support first appeared.
+.It Em AUTHORS
+Credits to the person or persons who wrote the code and/or documentation.
+Authors should generally be noted by both name and email address.
+.Pp
+See
+.Sx \&An .
+.It Em CAVEATS
+Common misuses and misunderstandings should be explained
+in this section.
+.It Em BUGS
+Known bugs, limitations, and work-arounds should be described
+in this section.
+.It Em SECURITY CONSIDERATIONS
+Documents any security precautions that operators should consider.
+.El
+.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, the following are equivalent:
+.Bd -literal -offset indent
+\&.Pp
+\&.\ \ \ \&Pp
+.Ed
+.Pp
+The syntax of a macro depends on its classification.
+In this section,
+.Sq \-arg
+refers to macro arguments, which may be followed by zero or more
+.Sq parm
+parameters;
+.Sq \&Yo
+opens the scope of a macro; and if specified,
+.Sq \&Yc
+closes it out.
+.Pp
+The
+.Em Callable
+column indicates that the macro may also be called by passing its name
+as an argument to another macro.
+If a macro is not callable but its name appears as an argument
+to another macro, it is interpreted as opaque text.
+For example,
+.Sq \&.Fl \&Sh
+produces
+.Sq Fl \&Sh .
+.Pp
+The
+.Em Parsed
+column indicates whether the macro may call other macros by receiving
+their names as arguments.
+If a macro is not parsed but the name of another macro appears
+as an argument, it is interpreted as opaque text.
+.Pp
+The
+.Em Scope
+column, if applicable, describes closure rules.
+.Ss Block full-explicit
+Multi-line scope closed by an explicit closing macro.
+All macros contains bodies; only
+.Sx \&Bf
+and
+.Pq optionally
+.Sx \&Bl
+contain a head.
+.Bd -literal -offset indent
+\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
+\(lBbody...\(rB
+\&.Yc
+.Ed
+.Pp
+.Bl -column -compact -offset indent "MacroX" "CallableX" "ParsedX" "closed by XXX"
+.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
+.It Sx \&Bd Ta \&No Ta \&No Ta closed by Sx \&Ed
+.It Sx \&Bf Ta \&No Ta \&No Ta closed by Sx \&Ef
+.It Sx \&Bk Ta \&No Ta \&No Ta closed by Sx \&Ek
+.It Sx \&Bl Ta \&No Ta \&No Ta closed by Sx \&El
+.It Sx \&Ed Ta \&No Ta \&No Ta opened by Sx \&Bd
+.It Sx \&Ef Ta \&No Ta \&No Ta opened by Sx \&Bf
+.It Sx \&Ek Ta \&No Ta \&No Ta opened by Sx \&Bk
+.It Sx \&El Ta \&No Ta \&No Ta opened by Sx \&Bl
+.El
+.Ss Block full-implicit
+Multi-line scope closed by end-of-file or implicitly by another macro.
+All macros have bodies; some
+.Po
+.Sx \&It Fl bullet ,
+.Fl hyphen ,
+.Fl dash ,
+.Fl enum ,
+.Fl item
+.Pc
+don't have heads; only one
+.Po
+.Sx \&It
+in
+.Sx \&Bl Fl column
+.Pc
+has multiple heads.
+.Bd -literal -offset indent
+\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead... \(lBTa head...\(rB\(rB
+\(lBbody...\(rB
+.Ed
+.Pp
+.Bl -column -compact -offset indent "MacroX" "CallableX" "ParsedX" "closed by XXXXXXXXXXX"
+.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
+.It Sx \&It Ta \&No Ta Yes Ta closed by Sx \&It , Sx \&El
+.It Sx \&Nd Ta \&No Ta \&No Ta closed by Sx \&Sh
+.It Sx \&Nm Ta \&No Ta Yes Ta closed by Sx \&Nm , Sx \&Sh , Sx \&Ss
+.It Sx \&Sh Ta \&No Ta \&No Ta closed by Sx \&Sh
+.It Sx \&Ss Ta \&No Ta \&No Ta closed by Sx \&Sh , Sx \&Ss
+.El
+.Pp
+Note that the
+.Sx \&Nm
+macro is a
+.Sx Block full-implicit
+macro only when invoked as the first macro
+in a
+.Em SYNOPSIS
+section line, else it is
+.Sx In-line .
+.Ss Block partial-explicit
+Like block full-explicit, but also with single-line scope.
+Each has at least a body and, in limited circumstances, a head
+.Po
+.Sx \&Fo ,
+.Sx \&Eo
+.Pc
+and/or tail
+.Pq Sx \&Ec .
+.Bd -literal -offset indent
+\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB
+\(lBbody...\(rB
+\&.Yc \(lBtail...\(rB
+
+\&.Yo \(lB\-arg \(lBparm...\(rB\(rB \(lBhead...\(rB \
+\(lBbody...\(rB \&Yc \(lBtail...\(rB
+.Ed
+.Pp
+.Bl -column "MacroX" "CallableX" "ParsedX" "closed by XXXX" -compact -offset indent
+.It Em Macro Ta Em Callable Ta Em Parsed Ta Em Scope
+.It Sx \&Ac Ta Yes Ta Yes Ta opened by Sx \&Ao
+.It Sx \&Ao Ta Yes Ta Yes Ta closed by Sx \&Ac
+.It Sx \&Bc Ta Yes Ta Yes Ta closed by Sx \&Bo
+.It Sx \&Bo Ta Yes Ta Yes Ta opened by Sx \&Bc
+.It Sx \&Brc Ta Yes Ta Yes Ta opened by Sx \&Bro
+.It Sx \&Bro Ta Yes Ta Yes Ta closed by Sx \&Brc
+.It Sx \&Dc Ta Yes Ta Yes Ta opened by Sx \&Do
+.It Sx \&Do Ta Yes Ta Yes Ta closed by Sx \&Dc
+.It Sx \&Ec Ta Yes Ta Yes Ta opened by Sx \&Eo
+.It Sx \&Eo Ta Yes Ta Yes Ta closed by Sx \&Ec
+.It Sx \&Fc Ta Yes Ta Yes Ta opened by Sx \&Fo
+.It Sx \&Fo Ta \&No Ta \&No Ta closed by Sx \&Fc
+.It Sx \&Oc Ta Yes Ta Yes Ta closed by Sx \&Oo
+.It Sx \&Oo Ta Yes Ta Yes Ta opened by Sx \&Oc
+.It Sx \&Pc Ta Yes Ta Yes Ta closed by Sx \&Po
+.It Sx \&Po Ta Yes Ta Yes Ta opened by Sx \&Pc
+.It Sx \&Qc Ta Yes Ta Yes Ta opened by Sx \&Oo
+.It Sx \&Qo Ta Yes Ta Yes Ta closed by Sx \&Oc
+.It Sx \&Re Ta \&No Ta \&No Ta opened by Sx \&Rs
+.It Sx \&Rs Ta \&No Ta \&No Ta closed by Sx \&Re
+.It Sx \&Sc Ta Yes Ta Yes Ta opened by Sx \&So
+.It Sx \&So Ta Yes Ta Yes Ta closed by Sx \&Sc
+.It Sx \&Xc Ta Yes Ta Yes Ta opened by Sx \&Xo
+.It Sx \&Xo Ta Yes Ta Yes Ta closed by Sx \&Xc