+.Sx \&Os .
+.Ss \&Dl
+One-line intended display. This is formatted as literal text and is
+useful for commands and invocations. It is followed by a newline.
+.Pp
+Examples:
+.D1 \&.Dl % mandoc mdoc.7 | less
+.Pp
+See also
+.Sx \&Bd
+and
+.Sx \&D1 .
+.Ss \&Do
+Begins a block enclosed by double quotes. Does not have any head
+arguments.
+.Pp
+Examples:
+.D1 \&.D1 \&Do April is the cruellest month \&Dc \e(em T.S. Eliot
+.Pp
+See also
+.Sx \&Dq .
+.Ss \&Dq
+Encloses its arguments in double quotes.
+.Pp
+Examples:
+.Bd -literal -offset indent -compact
+\&.Dq April is the cruellest month
+\e(em T.S. Eliot
+.Ed
+.Pp
+See also
+.Sx \&Do .
+.Ss \&Dt
+Document title. This is the mandatory second macro of any
+.Nm
+file. Its calling syntax is as follows:
+.Pp
+.D1 \. Ns Sx \&Dt Cm title section Op Cm volume | arch
+.Pp
+Its arguments are as follows:
+.Bl -tag -width Ds -offset Ds
+.It Cm title
+The document's title (name). This should be capitalised and is
+required.
+.It Cm section
+The manual section. This may be one of
+.Ar 1
+.Pq utilities ,
+.Ar 2
+.Pq system calls ,
+.Ar 3
+.Pq libraries ,
+.Ar 3p
+.Pq Perl libraries ,
+.Ar 4
+.Pq devices ,
+.Ar 5
+.Pq file formats ,
+.Ar 6
+.Pq games ,
+.Ar 7
+.Pq miscellaneous ,
+.Ar 8
+.Pq system utilities ,
+.Ar 9
+.Pq kernel functions ,
+.Ar X11
+.Pq X Window System ,
+.Ar X11R6
+.Pq X Window System ,
+.Ar unass
+.Pq unassociated ,
+.Ar local
+.Pq local system ,
+.Ar draft
+.Pq draft manual ,
+or
+.Ar paper
+.Pq paper .
+It is also required and should correspond to the manual's filename
+suffix.
+.It Cm volume
+This overrides the volume inferred from
+.Ar section .
+This field is optional, and if specified, must be one of
+.Ar USD
+.Pq users' supplementary documents ,
+.Ar PS1
+.Pq programmers' supplementary documents ,
+.Ar AMD
+.Pq administrators' supplementary documents ,
+.Ar SMM
+.Pq system managers' manuals ,
+.Ar URM
+.Pq users' reference manuals ,
+.Ar PRM
+.Pq programmers' reference manuals ,
+.Ar KM
+.Pq kernel manuals ,
+.Ar IND
+.Pq master index ,
+.Ar MMI
+.Pq master index ,
+.Ar LOCAL
+.Pq local manuals ,
+.Ar LOC
+.Pq local manuals ,
+or
+.Ar CON
+.Pq contributed manuals .
+.It Cm arch
+This specifies a specific relevant architecture. If
+.Cm volume
+is not provided, it may be used in its place, else it may be used
+subsequent that. It, too, is optional. It must be one of
+.Ar alpha ,
+.Ar amd64 ,
+.Ar amiga ,
+.Ar arc ,
+.Ar arm ,
+.Ar armish ,
+.Ar aviion ,
+.Ar hp300 ,
+.Ar hppa ,
+.Ar hppa64 ,
+.Ar i386 ,
+.Ar landisk ,
+.Ar loongson ,
+.Ar luna88k ,
+.Ar mac68k ,
+.Ar macppc ,
+.Ar mvme68k ,
+.Ar mvme88k ,
+.Ar mvmeppc ,
+.Ar pmax ,
+.Ar sgi ,
+.Ar socppc ,
+.Ar sparc ,
+.Ar sparc64 ,
+.Ar sun3 ,
+.Ar vax ,
+or
+.Ar zaurus .
+.El
+.Pp
+Examples:
+.D1 \&.Dt FOO 1
+.D1 \&.Dt FOO 4 KM
+.D1 \&.Dt FOO 9 i386
+.D1 \&.Dt FOO 9 KM i386
+.Pp
+See also
+.Sx \&Dd
+and
+.Sx \&Os .
+.Ss \&Dv
+Defined variables such as preprocessor constants.
+.Pp
+Examples:
+.D1 \&.Dv BUFSIZ
+.D1 \&.Dv STDOUT_FILENO
+.Pp
+See also
+.Sx \&Er .
+.Ss \&Dx
+Format the DragonFly BSD version provided as an argument, or a default
+value if no argument is provided.
+.Pp
+Examples:
+.D1 \&.Dx 2.4.1
+.D1 \&.Dx
+.Pp
+See also
+.Sx \&At ,
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Fx ,
+.Sx \&Nx ,
+.Sx \&Ox ,
+and
+.Sx \&Ux .
+.Ss \&Ec
+.Ss \&Ed
+.Ss \&Ef
+.Ss \&Ek
+.Ss \&El
+.Ss \&Em
+Denotes text that should be emphasised. Note that this is a
+presentation term and should not be used for stylistically decorating
+technical terms.
+.Pp
+Examples:
+.D1 \&.Em Warnings!
+.D1 \&.Em Remarks :
+.Ss \&En
+.Ss \&Eo
+.Ss \&Er
+Display error constants.
+.Pp
+Examples:
+.D1 \&.Er EPERM
+.D1 \&.Er ENOENT
+.Pp
+See also
+.Sx \&Dv .
+.Ss \&Es
+.Ss \&Ev
+Environmental variables such as those specified in
+.Xr environ 7 .
+.Pp
+Examples:
+.D1 \&.Ev DISPLAY
+.D1 \&.Ev PATH
+.Ss \&Ex
+Inserts text regarding a utility's exit values. This macro must have
+first the
+.Fl std
+argument specified, then an optional
+.Ar utility .
+If
+.Ar utility
+is not provided, the document's name as stipulated in
+.Sx \&Nm
+is provided.
+.Ss \&Fa
+.Ss \&Fc
+.Ss \&Fd
+.Ss \&Fl
+Command-line flag. Used when listing arguments to command-line
+utilities. Prints a fixed-width hyphen
+.Sq \-
+directly followed by each argument. If no arguments are provided, a hyphen is
+printed followed by a space. If the argument is a macro, a hyphen is
+prefixed to the subsequent macro output.
+.Pp
+Examples:
+.D1 \&.Fl a b c
+.D1 \&.Fl \&Pf a b
+.D1 \&.Fl
+.D1 \&.Op \&Fl o \&Ns \&Ar file
+.Pp
+See also
+.Sx \&Cm .
+.Ss \&Fn
+.Ss \&Fo
+.Ss \&Fr
+.Ss \&Ft
+.Ss \&Fx
+Format the FreeBSD version provided as an argument, or a default value
+if no argument is provided.
+.Pp
+Examples:
+.D1 \&.Fx 7.1
+.D1 \&.Fx
+.Pp
+See also
+.Sx \&At ,
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Dx ,
+.Sx \&Nx ,
+.Sx \&Ox ,
+and
+.Sx \&Ux .
+.Ss \&Hf
+.Ss \&Ic
+.Ss \&In
+.Ss \&It
+.Ss \&Lb
+.Ss \&Li
+.Ss \&Lk
+Format a hyperlink. The calling syntax is as follows:
+.Pp
+.D1 \. Ns Sx \&Lk Cm uri Op Cm name
+.Pp
+Examples:
+.D1 \&.Lk http://bsd.lv "The BSD.lv Project"
+.D1 \&.Lk http://bsd.lv
+.Pp
+See also
+.Sx \&Mt .
+.Ss \&Lp
+.Ss \&Ms
+.Ss \&Mt
+.Ss \&Nd
+.Ss \&Nm
+.Ss \&No
+.Ss \&Ns
+.Ss \&Nx
+Format the NetBSD version provided as an argument, or a default value if
+no argument is provided.
+.Pp
+Examples:
+.D1 \&.Nx 5.01
+.D1 \&.Nx
+.Pp
+See also
+.Sx \&At ,
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Dx ,
+.Sx \&Fx ,
+.Sx \&Ox ,
+and
+.Sx \&Ux .
+.Ss \&Oc
+.Ss \&Oo
+.Ss \&Op
+.Ss \&Os
+Document operating system version. This is the mandatory third macro of
+any
+.Nm
+file. Its calling syntax is as follows:
+.Pp
+.D1 \. Ns Sx \&Os Op Cm system
+.Pp
+The optional
+.Cm system
+parameter specifies the relevant operating system or environment. Left
+unspecified, it defaults to the local operating system version. This is
+the suggested form.
+.Pp
+Examples:
+.D1 \&.Os
+.D1 \&.Os KTH/CSC/TCS
+.D1 \&.Os BSD 4.3
+.Pp
+See also
+.Sx \&Dd
+and
+.Sx \&Dt .
+.Ss \&Ot
+Unknown usage.
+.Pp
+.Em Remarks :
+this macro has been deprecated.
+.Ss \&Ox
+Format the OpenBSD version provided as an argument, or a default value
+if no argument is provided.
+.Pp
+Examples:
+.D1 \&.Ox 4.5
+.D1 \&.Ox
+.Pp
+See also
+.Sx \&At ,
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Dx ,
+.Sx \&Fx ,
+.Sx \&Nx ,
+and
+.Sx \&Ux .
+.Ss \&Pa
+.Ss \&Pc
+.Ss \&Pf
+.Ss \&Po
+.Ss \&Pp
+.Ss \&Pq
+.Ss \&Qc
+.Ss \&Ql
+.Ss \&Qo
+.Ss \&Qq
+.Ss \&Re
+Closes a
+.Sx \&Rs
+block. Does not have any tail arguments.
+.Ss \&Rs
+Begins a bibliographic
+.Pq Dq reference
+block. Does not have any head arguments. The block macro may only
+contain
+.Sx \&%A ,
+.Sx \&%B ,
+.Sx \&%C ,
+.Sx \&%D ,
+.Sx \&%I ,
+.Sx \&%J ,
+.Sx \&%N ,
+.Sx \&%O ,
+.Sx \&%P ,
+.Sx \&%Q ,
+.Sx \&%R ,
+.Sx \&%T ,
+and
+.Sx \&%V
+child macros (at least one must be specified).
+.Pp
+Examples:
+.Bd -literal -offset indent -compact
+\&.Rs
+\&.%A J. E. Hopcroft
+\&.%A J. D. Ullman
+\&.%B Introduction to Automata Theory, Languages, and Computation
+\&.%I Addison-Wesley
+\&.%C Reading, Massachusettes
+\&.%D 1979
+\&.Re
+.Ed
+.Pp
+If an
+.Sx \&Rs
+block is used within a SEE ALSO section, a vertical space is asserted
+before the rendered output, else the block continues on the current
+line.
+.Ss \&Rv
+.Ss \&Sc
+.Ss \&Sh
+.Ss \&Sm
+.Ss \&So
+.Ss \&Sq
+.Ss \&Ss
+.Ss \&St
+.Ss \&Sx
+.Ss \&Sy
+.Ss \&Tn
+.Ss \&Ud
+.Ss \&Ux
+Format the UNIX name. Accepts no argument.
+.Pp
+Examples:
+.D1 \&.Ux
+.Pp
+See also
+.Sx \&At ,
+.Sx \&Bsx ,
+.Sx \&Bx ,
+.Sx \&Dx ,
+.Sx \&Fx ,
+.Sx \&Nx ,
+and
+.Sx \&Ox .
+.Ss \&Va
+.Ss \&Vt
+A variable type. This is also used for indicating global variables in the
+SYNOPSIS section, in which case a variable name is also specified. Note that
+it accepts
+.Sx Block partial-implicit
+syntax when invoked as the first macro in the SYNOPSIS section, else it
+accepts ordinary
+.Sx In-line
+syntax.
+.Pp
+Note that this should not be confused with
+.Sx \&Ft ,
+which is used for function return types.
+.Pp
+Examples:
+.D1 \&.Vt unsigned char
+.D1 \&.Vt extern const char * const sys_signame[] ;
+.Pp
+See also
+.Sx \&Ft
+and
+.Sx \&Va .
+.Ss \&Xc
+Close a scope opened by
+.Sx \&Xo .
+.Ss \&Xo
+Open an extension scope. This macro originally existed to extend the
+9-argument limit of troff; since this limit has been lifted, the macro
+has been deprecated.
+.Ss \&Xr
+Link to another manual
+.Pq Qq cross-reference .
+Its calling syntax is
+.Pp
+.D1 \. Ns Sx \&Xr Cm name section
+.Pp
+The
+.Cm name
+and
+.Cm section
+are the name and section of the linked manual. If
+.Cm section
+is followed by non-punctuation, an
+.Sx \&Ns
+is inserted into the token stream. This behaviour is for compatibility
+with