Updated: 2021/Apr/14


ROFF(7)                Miscellaneous Information Manual                ROFF(7)

NAME
     roff - roff language reference for mandoc

DESCRIPTION
     The roff language is a general purpose text formatting language.  Since
     traditional implementations of the mdoc(7) and man(7) manual formatting
     languages are based on it, many real-world manuals use small numbers of
     roff requests and escape sequences intermixed with their mdoc(7) or
     man(7) code.  To properly format such manuals, the mandoc(1) utility
     supports a subset of roff requests and escapes.  Even though this manual
     page lists all roff requests and escape sequences, it only contains
     partial information about requests not supported by mandoc(1) and about
     language features that do not matter for manual pages.  For complete roff
     manuals, consult the SEE ALSO section.

     Input lines beginning with the control character `.' are parsed for
     requests and macros.  Such lines are called "request lines" or "macro
     lines", respectively.  Requests change the processing state and
     manipulate the formatting; some macros also define the document structure
     and produce formatted output.  The single quote ("'") is accepted as an
     alternative control character, treated by mandoc(1) just like `.'

     Lines not beginning with control characters are called "text lines".
     They provide free-form text to be printed; the formatting of the text
     depends on the respective processing context.

LANGUAGE SYNTAX
     roff documents may contain only graphable 7-bit ASCII characters, the
     space character, and, in certain circumstances, the tab character.  The
     backslash character `\' indicates the start of an escape sequence, used
     for example for Comments and Special Characters.  For a complete listing
     of escape sequences, consult the ESCAPE SEQUENCE REFERENCE below.

   Comments
     Text following an escaped double-quote `\"', whether in a request, macro,
     or text line, is ignored to the end of the line.  A request line
     beginning with a control character and comment escape `.\"' is also
     ignored.  Furthermore, request lines with only a control character and
     optional trailing whitespace are stripped from input.

     Examples:
           .\" This is a comment line.
           .\" The next line is ignored:
           .
           .Sh EXAMPLES \" This is a comment, too.
           example text \" And so is this.

   Special Characters
     Special characters are used to encode special glyphs and are rendered
     differently across output media.  They may occur in request, macro, and
     text lines.  Sequences begin with the escape character `\' followed by
     either an open-parenthesis `(' for two-character sequences; an open-
     bracket `[' for n-character sequences (terminated at a close-bracket
     `]'); or a single one character sequence.

     Examples:
           \(em    Two-letter em dash escape.
           \e      One-letter backslash escape.

     See mandoc_char(7) for a complete list.

   Font Selection
     In mdoc(7) and man(7) documents, fonts are usually selected with macros.
     The \f escape sequence and the ft request can be used to manually change
     the font, but this is not recommended in mdoc(7) documents.  Such manual
     font changes are overridden by many subsequent macros.

     The following fonts are supported:

           B   Bold font.
           BI  A font that is both bold and italic.
           CB  Bold constant width font.  Same as B in terminal output.
           CI  Italic constant width font.  Same as I in terminal output.
           CR  Regular constant width font.  Same as R in terminal output.
           CW  An alias for CR.
           I   Italic font.
           P   Return to the previous font.  If a macro caused a font change
               since the last \f eascape sequence or ft request, this returns
               to the font before the last font change in the macro rather
               than to the font before the last manual font change.
           R   Roman font.  This is the default font.
           1   An alias for R.
           2   An alias for I.
           3   An alias for B.
           4   An alias for BI.

     Examples:
           \fBbold\fR
                   Write in bold, then switch to regular font mode.
           \fIitalic\fP
                   Write in italic, then return to previous font mode.
           \f(BIbold italic\fP
                   Write in bboolldd iittaalliicc, then return to previous font mode.

   Whitespace
     Whitespace consists of the space character.  In text lines, whitespace is
     preserved within a line.  In request and macro lines, whitespace delimits
     arguments and is discarded.

     Unescaped trailing spaces are stripped from text line input unless in a
     literal context.  In general, trailing whitespace on any input line is
     discouraged for reasons of portability.  In the rare case that a space
     character is needed at the end of an input line, it may be forced by
     `\ \&'.

     Literal space characters can be produced in the output using escape
     sequences.  In macro lines, they can also be included in arguments using
     quotation; see MACRO SYNTAX for details.

     Blank text lines, which may include whitespace, are only permitted within
     literal contexts.  If the first character of a text line is a space, that
     line is printed with a leading newline.

   Scaling Widths
     Many requests and macros support scaled widths for their arguments.  The
     syntax for a scaled width is `[+-]?[0-9]*.[0-9]*[:unit:]', where a
     decimal must be preceded or followed by at least one digit.

     The following scaling units are accepted:

           c       centimetre
           i       inch
           P       pica (1/6 inch)
           p       point (1/72 inch)
           f       scale `u' by 65536
           v       default vertical span
           m       width of rendered `m' (em) character
           n       width of rendered `n' (en) character
           u       default horizontal span for the terminal
           M       mini-em (1/100 em)

     Using anything other than `m', `n', or `v' is necessarily non-portable
     across output media.  See COMPATIBILITY.

     If a scaling unit is not provided, the numerical value is interpreted
     under the default rules of `v' for vertical spaces and `u' for horizontal
     ones.

     Examples:
           .Bl -tag -width 2i  two-inch tagged list indentation in mdoc(7)
           .HP 2i              two-inch tagged list indentation in man(7)
           .sp 2v              two vertical spaces

   Sentence Spacing
     Each sentence should terminate at the end of an input line.  By doing
     this, a formatter 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
     (`)', `]', `'', `"').

     The proper spacing is also intelligently preserved if a sentence ends at
     the boundary of a macro line.

     Examples:
           Do not end sentences mid-line like this.  Instead,
           end a sentence like this.
           A macro would end like this:
           .Xr mandoc 1 .

REQUEST SYNTAX
     A request or macro line consists of:

     1.   the control character `.' or `'' at the beginning of the line,
     2.   optionally an arbitrary amount of whitespace,
     3.   the name of the request or the macro, which is one word of arbitrary
          length, terminated by whitespace,
     4.   and zero or more arguments delimited by whitespace.

     Thus, the following request lines are all equivalent:

           .ig end
           .ig    end
           .   ig end

MACRO SYNTAX
     Macros are provided by the mdoc(7) and man(7) languages and can be
     defined by the de request.  When called, they follow the same syntax as
     requests, except that macro arguments may optionally be quoted by
     enclosing them in double quote characters (`"').  Quoted text, even if it
     contains whitespace or would cause a macro invocation when unquoted, is
     always considered literal text.  Inside quoted text, pairs of double
     quote characters (`""') resolve to single double quote characters.

     To be recognised as the beginning of a quoted argument, the opening quote
     character must be preceded by a space character.  A quoted argument
     extends to the next double quote character that is not part of a pair, or
     to the end of the input line, whichever comes earlier.  Leaving out the
     terminating double quote character at the end of the line is discouraged.
     For clarity, if more arguments follow on the same input line, it is
     recommended to follow the terminating double quote character by a space
     character; in case the next character after the terminating double quote
     character is anything else, it is regarded as the beginning of the next,
     unquoted argument.

     Both in quoted and unquoted arguments, pairs of backslashes (`\\')
     resolve to single backslashes.  In unquoted arguments, space characters
     can alternatively be included by preceding them with a backslash (`\ '),
     but quoting is usually better for clarity.

     Examples:
           .Fn strlen "const char *s"
                   Group arguments "const char *s" into one function argument.
                   If unspecified, "const", "char", and "*s" would be
                   considered separate arguments.
           .Op "Fl a"
                   Consider "Fl a" as literal text instead of a flag macro.

REQUEST REFERENCE
     The mandoc(1) roff parser recognises the following requests.  For
     requests marked as "ignored" or "unsupported", any arguments are ignored,
     and the number of arguments is not checked.

     ab [message]
             Abort processing.  Currently unsupported.

     ad [b | c | l | n | r]
             Set line adjustment mode for subsequent text.  Currently ignored.

     af registername format
             Assign an output format to a number register.  Currently ignored.

     aln newname oldname
             Create an alias for a number register.  Currently unsupported.

     als newname oldname
             Create an alias for a request, string, macro, or diversion.

     am macroname [endmacro]
             Append to a macro definition.  The syntax of this request is the
             same as that of de.

     am1 macroname [endmacro]
             Append to a macro definition, switching roff compatibility mode
             off during macro execution (groff extension).  The syntax of this
             request is the same as that of de1.  Since mandoc(1) does not
             implement roff compatibility mode at all, it handles this request
             as an alias for am.

     ami macrostring [endstring]
             Append to a macro definition, specifying the macro name
             indirectly (groff extension).  The syntax of this request is the
             same as that of dei.

     ami1 macrostring [endstring]
             Append to a macro definition, specifying the macro name
             indirectly and switching roff compatibility mode off during macro
             execution (groff extension).  The syntax of this request is the
             same as that of dei1.  Since mandoc(1) does not implement roff
             compatibility mode at all, it handles this request as an alias
             for ami.

     as stringname [string]
             Append to a user-defined string.  The syntax of this request is
             the same as that of ds.  If a user-defined string with the
             specified name does not yet exist, it is set to the empty string
             before appending.

     as1 stringname [string]
             Append to a user-defined string, switching roff compatibility
             mode off during macro execution (groff extension).  The syntax of
             this request is the same as that of ds1.  Since mandoc(1) does
             not implement roff compatibility mode at all, it handles this
             request as an alias for as.

     asciify divname
             Fully unformat a diversion.  Currently unsupported.

     backtrace
             Print a backtrace of the input stack.  This is a groff extension
             and currently ignored.

     bd font [curfont] [offset]
             Artificially embolden by repeated printing with small shifts.
             Currently ignored.

     bleedat left top width height
             Set the BleedBox page parameter for PDF generation.  This is a
             Heirloom extension and currently ignored.

     blm macroname
             Set a blank line trap.  Currently unsupported.

     box divname
             Begin a diversion without including a partially filled line.
             Currently unsupported.

     boxa divname
             Add to a diversion without including a partially filled line.
             Currently unsupported.

     bp [+|-]pagenumber
             Begin a new page.  Currently ignored.

     BP source height width position offset flags label
             Define a frame and place a picture in it.  This is a Heirloom
             extension and currently unsupported.

     br      Break the output line.

     break   Break out of a while loop.  Currently unsupported.

     breakchar char ...
             Optional line break characters.  This is a Heirloom extension and
             currently ignored.

     brnl N  Break output line after the next N input lines.  This is a
             Heirloom extension and currently ignored.

     brp     Break and spread output line.  Currently, this is implemented as
             an alias for br.

     brpnl N
             Break and spread output line after the next N input lines.  This
             is a Heirloom extension and currently ignored.

     c2 [char]
             Change the no-break control character.  Currently unsupported.

     cc [char]
             Change the control character.  If char is not specified, the
             control character is reset to `.'.  Trailing characters are
             ignored.

     ce [N]  Center the next N input lines without filling.  N defaults to 1.
             An argument of 0 or less ends centering.  Currently, high level
             macros abort centering.

     cf filename
             Output the contents of a file.  Ignored because insecure.

     cflags flags char ...
             Set character flags.  This is a groff extension and currently
             ignored.

     ch macroname [dist]
             Change a trap location.  Currently ignored.

     char glyph [string]
             Define or redefine the ASCII character or character escape
             sequence glyph to be rendered as string, which can be empty.
             Only partially supported in mandoc(1); may interact incorrectly
             with tr.

     chop stringname
             Remove the last character from a macro, string, or diversion.
             Currently unsupported.

     class classname char ...
             Define a character class.  This is a groff extension and
             currently ignored.

     close streamname
             Close an open file.  Ignored because insecure.

     CL color text
             Print text in color.  This is a Heirloom extension and currently
             unsupported.

     color [1 | 0]
             Activate or deactivate colors.  This is a groff extension and
             currently ignored.

     composite from to
             Define a name component for composite glyph names.  This is a
             groff extension and currently unsupported.

     continue
             Immediately start the next iteration of a while loop.  Currently
             unsupported.

     cp [1 | 0]
             Switch roff compatibility mode on or off.  Currently ignored.

     cropat left top width height
             Set the CropBox page parameter for PDF generation.  This is a
             Heirloom extension and currently ignored.

     cs font [width [emsize]]
             Constant character spacing mode.  Currently ignored.

     cu [N]  Underline next N input lines including whitespace.  Currently
             ignored.

     da divname
             Append to a diversion.  Currently unsupported.

     dch macroname [dist]
             Change a trap location in the current diversion.  This is a
             Heirloom extension and currently unsupported.

     de macroname [endmacro]
             Define a roff macro.  Its syntax can be either

                   .de macroname
                   definition
                   ..

             or

                   .de macroname endmacro
                   definition
                   .endmacro

             Both forms define or redefine the macro macroname to represent
             the definition, which may consist of one or more input lines,
             including the newline characters terminating each line,
             optionally containing calls to roff requests, roff macros or
             high-level macros like man(7) or mdoc(7) macros, whichever
             applies to the document in question.

             Specifying a custom endmacro works in the same way as for ig;
             namely, the call to `.endmacro' first ends the definition, and
             after that, it is also evaluated as a roff request or roff macro,
             but not as a high-level macro.

             The macro can be invoked later using the syntax

                   .macroname [argument [argument ...]]

             Regarding argument parsing, see MACRO SYNTAX above.

             The line invoking the macro will be replaced in the input stream
             by the definition, replacing all occurrences of \\$N, where N is
             a digit, by the Nth argument.  For example,

                   .de ZN
                   \fI\^\\$1\^\fP\\$2
                   ..
                   .ZN XtFree .

             produces

                   \fI\^XtFree\^\fP.

             in the input stream, and thus in the output: XtFree.  Each
             occurrence of \\$* is replaced with all the arguments, joined
             together with single space characters.  The variant \\$@ is
             similar, except that each argument is individually quoted.

             Since macros and user-defined strings share a common string
             table, defining a macro macroname clobbers the user-defined
             string macroname, and the definition can also be printed using
             the `\*' string interpolation syntax described below ds, but this
             is rarely useful because every macro definition contains at least
             one explicit newline character.

             In order to prevent endless recursion, both groff and mandoc(1)
             limit the stack depth for expanding macros and strings to a
             large, but finite number, and mandoc(1) also limits the length of
             the expanded input line.  Do not rely on the exact values of
             these limits.

     de1 macroname [endmacro]
             Define a roff macro that will be executed with roff compatibility
             mode switched off during macro execution.  This is a groff
             extension.  Since mandoc(1) does not implement roff compatibility
             mode at all, it handles this request as an alias for de.

     defcolor newname scheme component ...
             Define a color name.  This is a groff extension and currently
             ignored.

     dei macrostring [endstring]
             Define a roff macro, specifying the macro name indirectly (groff
             extension).  The syntax of this request is the same as that of
             de.  The effect is the same as:

                   .de \*[macrostring] [\*[endstring]]

     dei1 macrostring [endstring]
             Define a roff macro that will be executed with roff compatibility
             mode switched off during macro execution, specifying the macro
             name indirectly (groff extension).  Since mandoc(1) does not
             implement roff compatibility mode at all, it handles this request
             as an alias for dei.

     device string ...

     devicem stringname
             These two requests only make sense with the groff-specific
             intermediate output format and are unsupported.

     di divname
             Begin a diversion.  Currently unsupported.

     do command [argument ...]
             Execute roff request or macro line with compatibility mode
             disabled.  Currently unsupported.

     ds stringname [["]string]
             Define a user-defined string.  The stringname and string
             arguments are space-separated.  If the string begins with a
             double-quote character, that character will not be part of the
             string.  All remaining characters on the input line form the
             string, including whitespace and double-quote characters, even
             trailing ones.

             The string can be interpolated into subsequent text by using
             \*[stringname] for a stringname of arbitrary length, or \*(NN or
             \*N if the length of stringname is two or one characters,
             respectively.  Interpolation can be prevented by escaping the
             leading backslash; that is, an asterisk preceded by an even
             number of backslashes does not trigger string interpolation.

             Since user-defined strings and macros share a common string
             table, defining a string stringname clobbers the macro
             stringname, and the stringname used for defining a string can
             also be invoked as a macro, in which case the following input
             line will be appended to the string, forming a new input line
             passed to the roff parser.  For example,

                   .ds badidea .S
                   .badidea
                   H SYNOPSIS

             invokes the SH macro when used in a man(7) document.  Such abuse
             is of course strongly discouraged.

     ds1 stringname [["]string]
             Define a user-defined string that will be expanded with roff
             compatibility mode switched off during string expansion.  This is
             a groff extension.  Since mandoc(1) does not implement roff
             compatibility mode at all, it handles this request as an alias
             for ds.

     dwh dist macroname
             Set a location trap in the current diversion.  This is a Heirloom
             extension and currently unsupported.

     dt [dist macroname]
             Set a trap within a diversion.  Currently unsupported.

     ec [char]
             Enable the escape mechanism and change the escape character.  The
             char argument defaults to the backslash (`\').

     ecr     Restore the escape character.  Currently unsupported.

     ecs     Save the escape character.  Currently unsupported.

     el body
             The "else" half of an if/else conditional.  Pops a result off the
             stack of conditional evaluations pushed by ie and uses it as its
             conditional.  If no stack entries are present (e.g., due to no
             prior ie calls) then false is assumed.  The syntax of this
             request is similar to if except that the conditional is missing.

     em macroname
             Set a trap at the end of input.  Currently unsupported.

     EN      End an equation block.  See EQ.

     eo      Disable the escape mechanism completely.

     EP      End a picture started by BP.  This is a Heirloom extension and
             currently unsupported.

     EQ      Begin an equation block.  See eqn(7) for a description of the
             equation language.

     errprint message
             Print a string like an error message.  This is a Heirloom
             extension and currently ignored.

     ev [envname]
             Switch to another environment.  Currently unsupported.

     evc [envname]
             Copy an environment into the current environment.  Currently
             unsupported.

     ex      Abort processing and exit.  Currently unsupported.

     fallback curfont font ...
             Select the fallback sequence for a font.  This is a Heirloom
             extension and currently ignored.

     fam [familyname]
             Change the font family.  This is a groff extension and currently
             ignored.

     fc [delimchar [padchar]]
             Define a delimiting and a padding character for fields.
             Currently unsupported.

     fchar glyphname [string]
             Define a fallback glyph.  Currently unsupported.

     fcolor colorname
             Set the fill color for \D objects.  This is a groff extension and
             currently ignored.

     fdeferlig font string ...
             Defer ligature building.  This is a Heirloom extension and
             currently ignored.

     feature +|-name
             Enable or disable an OpenType feature.  This is a Heirloom
             extension and currently ignored.

     fi      Break the output line and switch to fill mode, which is active by
             default but can be ended with the nf request.  In fill mode,
             input from subsequent input lines is added to the same output
             line until the next word no longer fits, at which point the
             output line is broken.  This request is implied by the mdoc(7) Sh
             macro and by the man(7) SH, SS, and EE macros.

     fkern font minkern
             Control the use of kerning tables for a font.  This is a Heirloom
             extension and currently ignored.

     fl      Flush output.  Currently ignored.

     flig font string char ...
             Define ligatures.  This is a Heirloom extension and currently
             ignored.

     fp position font [filename]
             Assign font position.  Currently ignored.

     fps mapname ...
             Mount a font with a special character map.  This is a Heirloom
             extension and currently ignored.

     fschar font glyphname [string]
             Define a font-specific fallback glyph.  This is a groff extension
             and currently unsupported.

     fspacewidth font [afmunits]
             Set a font-specific width for the space character.  This is a
             Heirloom extension and currently ignored.

     fspecial curfont [font ...]
             Conditionally define a special font.  This is a groff extension
             and currently ignored.

     ft [font]
             Change the font; see Font Selection.  The font argument defaults
             to P.

     ftr newname [oldname]
             Translate font name.  This is a groff extension and currently
             ignored.

     fzoom font [permille]
             Zoom font size.  Currently ignored.

     gcolor [colorname]
             Set glyph color.  This is a groff extension and currently
             ignored.

     hc [char]
             Set the hyphenation character.  Currently ignored.

     hcode char code ...
             Set hyphenation codes of characters.  Currently ignored.

     hidechar font char ...
             Hide characters in a font.  This is a Heirloom extension and
             currently ignored.

     hla language
             Set hyphenation language.  This is a groff extension and
             currently ignored.

     hlm [number]
             Set maximum number of consecutive hyphenated lines.  Currently
             ignored.

     hpf filename
             Load hyphenation pattern file.  This is a groff extension and
             currently ignored.

     hpfa filename
             Load hyphenation pattern file, appending to the current patterns.
             This is a groff extension and currently ignored.

     hpfcode code code ...
             Define mapping values for character codes in hyphenation
             patterns.  This is a groff extension and currently ignored.

     hw word ...
             Specify hyphenation points in words.  Currently ignored.

     hy [mode]
             Set automatic hyphenation mode.  Currently ignored.

     hylang language
             Set hyphenation language.  This is a Heirloom extension and
             currently ignored.

     hylen nchar
             Minimum word length for hyphenation.  This is a Heirloom
             extension and currently ignored.

     hym [length]
             Set hyphenation margin.  This is a groff extension and currently
             ignored.

     hypp penalty ...
             Define hyphenation penalties.  This is a Heirloom extension and
             currently ignored.

     hys [length]
             Set hyphenation space.  This is a groff extension and currently
             ignored.

     ie condition body
             The "if" half of an if/else conditional.  The result of the
             conditional is pushed into a stack used by subsequent invocations
             of el, which may be separated by any intervening input (or not
             exist at all).  Its syntax is equivalent to if.

     if condition body
             Begin a conditional.  This request can also be written as
             follows:

                   .if condition \{body
                   body ...\}

                   .if condition \{\
                   body ...
                   .\}

             The condition is a boolean expression.  Currently, mandoc(1)
             supports the following subset of roff conditionals:

                If `!' is prefixed to condition, it is logically inverted.

                If the first character of condition is `n' (nroff mode) or
                 `o' (odd page), it evaluates to true, and the body starts
                 with the next character.

                If the first character of condition is `e' (even page), `t'
                 (troff mode), or `v' (vroff mode), it evaluates to false, and
                 the body starts with the next character.

                If the first character of condition is `c' (character
                 available), it evaluates to true if the following character
                 is an ASCII character or a valid character escape sequence,
                 or to false otherwise.  The body starts with the character
                 following that next character.

                If the first character of condition is `d', it evaluates to
                 true if the rest of condition is the name of an existing user
                 defined macro or string; otherwise, it evaluates to false.

                If the first character of condition is `r', it evaluates to
                 true if the rest of condition is the name of an existing
                 number register; otherwise, it evaluates to false.

                If the condition starts with a parenthesis or with an
                 optionally signed integer number, it is evaluated according
                 to the rules of Numerical expressions explained below.  It
                 evaluates to true if the result is positive, or to false if
                 the result is zero or negative.

                Otherwise, the first character of condition is regarded as a
                 delimiter and it evaluates to true if the string extending
                 from its first to its second occurrence is equal to the
                 string extending from its second to its third occurrence.

                If condition cannot be parsed, it evaluates to false.

             If a conditional is false, its children are not processed, but
             are syntactically interpreted to preserve the integrity of the
             input document.  Thus,

                   .if t .ig

             will discard the `.ig', which may lead to interesting results,
             but

                   .if t .if t \{\

             will continue to syntactically interpret to the block close of
             the final conditional.  Sub-conditionals, in this case, obviously
             inherit the truth value of the parent.

             If the body section is begun by an escaped brace `\{', scope
             continues until the end of the input line containing the matching
             closing-brace escape sequence `\}'.  If the body is not enclosed
             in braces, scope continues until the end of the line.  If the
             condition is followed by a body on the same line, whether after a
             brace or not, then requests and macros must begin with a control
             character.  It is generally more intuitive, in this case, to
             write

                   .if condition \{\
                   .request
                   .\}

             than having the request or macro follow as

                   .if condition \{.request

             The scope of a conditional is always parsed, but only executed if
             the conditional evaluates to true.

             Note that the `\}' is converted into a zero-width escape sequence
             if not passed as a standalone macro `.\}'.  For example,

                   .Fl a \} b

             will result in `\}' being considered an argument of the `Fl'
             macro.

     ig [endmacro]
             Ignore input.  Its syntax can be either

                   .ig
                   ignored text
                   ..

             or

                   .ig endmacro
                   ignored text
                   .endmacro

             In the first case, input is ignored until a `..' request is
             encountered on its own line.  In the second case, input is
             ignored until the specified `.endmacro' is encountered.  Do not
             use the escape character `\' anywhere in the definition of
             endmacro; it would cause very strange behaviour.

             When the endmacro is a roff request or a roff macro, like in

                   .ig if

             the subsequent invocation of if will first terminate the ignored
             text, then be invoked as usual.  Otherwise, it only terminates
             the ignored text, and arguments following it or the `..' request
             are discarded.

     in [[+|-]width]
             Change indentation.  See man(7).  Ignored in mdoc(7).

     index register stringname substring
             Find a substring in a string.  This is a Heirloom extension and
             currently unsupported.

     it expression macro
             Set an input line trap.  The named macro will be invoked after
             processing the number of input text lines specified by the
             numerical expression.  While evaluating the expression, the unit
             suffixes described below Scaling Widths are ignored.

     itc expression macro
             Set an input line trap, not counting lines ending with \c.
             Currently unsupported.

     IX class keystring
             To support the generation of a table of contents, pod2man(1)
             emits this user-defined macro, usually without defining it.  To
             avoid reporting large numbers of spurious errors, mandoc(1)
             ignores it.

     kern [1 | 0]
             Switch kerning on or off.  Currently ignored.

     kernafter font char ... afmunits ...
             Increase kerning after some characters.  This is a Heirloom
             extension and currently ignored.

     kernbefore font char ... afmunits ...
             Increase kerning before some characters.  This is a Heirloom
             extension and currently ignored.

     kernpair font char ... font char ... afmunits
             Add a kerning pair to the kerning table.  This is a Heirloom
             extension and currently ignored.

     lc [glyph]
             Define a leader repetition character.  Currently unsupported.

     lc_ctype localename
             Set the LC_CTYPE locale.  This is a Heirloom extension and
             currently unsupported.

     lds macroname string
             Define a local string.  This is a Heirloom extension and
             currently unsupported.

     length register string
             Count the number of input characters in a string.  Currently
             unsupported.

     letadj lspmin lshmin letss lspmax lshmax
             Dynamic letter spacing and reshaping.  This is a Heirloom
             extension and currently ignored.

     lf lineno [filename]
             Change the line number for error messages.  Ignored because
             insecure.

     lg [1 | 0]
             Switch the ligature mechanism on or off.  Currently ignored.

     lhang font char ... afmunits
             Hang characters at left margin.  This is a Heirloom extension and
             currently ignored.

     linetabs [1 | 0]
             Enable or disable line-tabs mode.  This is a groff extension and
             currently unsupported.

     ll [[+|-]width]
             Change the output line length.  If the width argument is omitted,
             the line length is reset to its previous value.  The default
             setting for terminal output is 78n.  If a sign is given, the line
             length is added to or subtracted from; otherwise, it is set to
             the provided value.  Using this request in new manuals is
             discouraged for several reasons, among others because it
             overrides the mandoc(1) -O width command line option.

     lnr register [+|-]value [increment]
             Set local number register.  This is a Heirloom extension and
             currently unsupported.

     lnrf register [+|-]value [increment]
             Set local floating-point register.  This is a Heirloom extension
             and currently unsupported.

     lpfx string
             Set a line prefix.  This is a Heirloom extension and currently
             unsupported.

     ls [factor]
             Set line spacing.  It takes one integer argument specifying the
             vertical distance of subsequent output text lines measured in v
             units.  Currently ignored.

     lsm macroname
             Set a leading spaces trap.  This is a groff extension and
             currently unsupported.

     lt [[+|-]width]
             Set title line length.  Currently ignored.

     mc glyph [dist]
             Print margin character in the right margin.  The dist is
             currently ignored; instead, 1n is used.

     mediasize media
             Set the device media size.  This is a Heirloom extension and
             currently ignored.

     minss width
             Set minimum word space.  This is a Heirloom extension and
             currently ignored.

     mk [register]
             Mark vertical position.  Currently ignored.

     mso filename
             Load a macro file using the search path.  Ignored because
             insecure.

     na      Disable adjusting without changing the adjustment mode.
             Currently ignored.

     ne [height]
             Declare the need for the specified minimum vertical space before
             the next trap or the bottom of the page.  Currently ignored.

     nf      Break the output line and switch to no-fill mode.  Subsequent
             input lines are kept together on the same output line even when
             exceeding the right margin, and line breaks in subsequent input
             cause output line breaks.  This request is implied by the mdoc(7)
             Bd -unfilled and Bd -literal macros and by the man(7) EX macro.
             The fi request switches back to the default fill mode.

     nh      Turn off automatic hyphenation mode.  Currently ignored.

     nhychar char ...
             Define hyphenation-inhibiting characters.  This is a Heirloom
             extension and currently ignored.

     nm [start [inc [space [indent]]]]
             Print line numbers.  Currently unsupported.

     nn [number]
             Temporarily turn off line numbering.  Currently unsupported.

     nop body
             Execute the rest of the input line as a request, macro, or text
             line, skipping the nop request and any space characters
             immediately following it.  This is mostly used to indent text
             lines inside macro definitions.

     nr register [+|-]expression [stepsize]
             Define or change a register.  A register is an arbitrary string
             value that defines some sort of state, which influences parsing
             and/or formatting.  For the syntax of expression, see Numerical
             expressions below.  If it is prefixed by a sign, the register
             will be incremented or decremented instead of assigned to.

             The stepsize is used by the \n+ auto-increment feature.  It
             remains unchanged when omitted while changing an existing
             register, and it defaults to 0 when defining a new register.

             The following register is handled specially:

             nS      If set to a positive integer value, certain mdoc(7)
                     macros will behave in the same way as in the SYNOPSIS
                     section.  If set to 0, these macros will behave in the
                     same way as outside the SYNOPSIS section, even when
                     called within the SYNOPSIS section itself.  Note that
                     starting a new mdoc(7) section with the Sh macro will
                     reset this register.

     nrf register [+|-]expression [increment]
             Define or change a floating-point register.  This is a Heirloom
             extension and currently unsupported.

     nroff   Force nroff mode.  This is a groff extension and currently
             ignored.

     ns      Turn on no-space mode.  Currently ignored.

     nx [filename]
             Abort processing of the current input file and process another
             one.  Ignored because insecure.

     open stream file
             Open a file for writing.  Ignored because insecure.

     opena stream file
             Open a file for appending.  Ignored because insecure.

     os      Output saved vertical space.  Currently ignored.

     output string
             Output directly to intermediate output.  Not supported.

     padj [1 | 0]
             Globally control paragraph-at-once adjustment.  This is a
             Heirloom extension and currently ignored.

     papersize media
             Set the paper size.  This is a Heirloom extension and currently
             ignored.

     pc [char]
             Change the page number character.  Currently ignored.

     pev     Print environments.  This is a groff extension and currently
             ignored.

     pi command
             Pipe output to a shell command.  Ignored because insecure.

     PI      Low-level request used by BP.  This is a Heirloom extension and
             currently unsupported.

     pl [[+|-]height]
             Change page length.  Currently ignored.

     pm      Print names and sizes of macros, strings, and diversions to
             standard error output.  Currently ignored.

     pn [+|-]number
             Change the page number of the next page.  Currently ignored.

     pnr     Print all number registers on standard error output.  Currently
             ignored.

     po [[+|-]offset]
             Set a horizontal page offset.  If no argument is specified, the
             page offset is reverted to its previous value.  If a sign is
             specified, the new page offset is calculated relative to the
             current one; otherwise, it is absolute.  The argument follows the
             syntax of Scaling Widths and the default scaling unit is m.

     ps [[+|-]size]
             Change point size.  Currently ignored.

     psbb filename
             Retrieve the bounding box of a PostScript file.  Currently
             unsupported.

     pshape indent length ...
             Set a special shape for the current paragraph.  This is a
             Heirloom extension and currently unsupported.

     pso command
             Include output of a shell command.  Ignored because insecure.

     ptr     Print the names and positions of all traps on standard error
             output.  This is a groff extension and currently ignored.

     pvs [[+|-]height]
             Change post-vertical spacing.  This is a groff extension and
             currently ignored.

     rchar glyph ...
             Remove glyph definitions.  Currently unsupported.

     rd [prompt [argument ...]]
             Read from standard input.  Currently ignored.

     recursionlimit maxrec maxtail
             Set the maximum stack depth for recursive macros.  This is a
             Heirloom extension and currently ignored.

     return [twice]
             Exit the presently executed macro and return to the caller.  The
             argument is currently ignored.

     rfschar font glyph ...
             Remove font-specific fallback glyph definitions.  Currently
             unsupported.

     rhang font char ... afmunits
             Hang characters at right margin.  This is a Heirloom extension
             and currently ignored.

     rj [N]  Justify the next N input lines to the right margin without
             filling.  N defaults to 1.  An argument of 0 or less ends right
             adjustment.

     rm macroname
             Remove a request, macro or string.

     rn oldname newname
             Rename a request, macro, diversion, or string.  In mandoc(1),
             user-defined macros, mdoc(7) and man(7) macros, and user-defined
             strings can be renamed, but renaming of predefined strings and of
             roff requests is not supported, and diversions are not
             implemented at all.

     rnn oldname newname
             Rename a number register.  Currently unsupported.

     rr register
             Remove a register.

     rs      End no-space mode.  Currently ignored.

     rt [dist]
             Return to marked vertical position.  Currently ignored.

     schar glyph [string]
             Define global fallback glyph.  This is a groff extension and
             currently unsupported.

     sentchar char ...
             Define sentence-ending characters.  This is a Heirloom extension
             and currently ignored.

     shc [glyph]
             Change the soft hyphen character.  Currently ignored.

     shift [number]
             Shift macro arguments number times, by default once: \\$i becomes
             what \\$i+number was.  Also decrement \n(.$ by number.

     sizes size ...
             Define permissible point sizes.  This is a groff extension and
             currently ignored.

     so filename
             Include a source file.  The file is read and its contents
             processed as input in place of the so request line.  To avoid
             inadvertent inclusion of unrelated files, mandoc(1) only accepts
             relative paths not containing the strings "../" and "/..".

             This request requires man(1) to change to the right directory
             before calling mandoc(1), per convention to the root of the
             manual tree.  Typical usage looks like:

                   .so man3/Xcursor.3

             As the whole concept is rather fragile, the use of so is
             discouraged.  Use ln(1) instead.

     sp [height]
             Break the output line and emit vertical space.  The argument
             follows the syntax of Scaling Widths and defaults to one blank
             line (1v).

     spacewidth [1 | 0]
             Set the space width from the font metrics file.  This is a
             Heirloom extension and currently ignored.

     special [font ...]
             Define a special font.  This is a groff extension and currently
             ignored.

     spreadwarn [width]
             Warn about wide spacing between words.  Currently ignored.

     ss wordspace [sentencespace]
             Set space character size.  Currently ignored.

     sty position style
             Associate style with a font position.  This is a groff extension
             and currently ignored.

     substring stringname startpos [endpos]
             Replace a user-defined string with a substring.  Currently
             unsupported.

     sv [height]
             Save vertical space.  Currently ignored.

     sy command
             Execute shell command.  Ignored because insecure.

     T&      Re-start a table layout, retaining the options of the prior table
             invocation.  See TS.

     ta [width ... [T width ...]]
             Set tab stops.  Each width argument follows the syntax of Scaling
             Widths.  If prefixed by a plus sign, it is relative to the
             previous tab stop.  The arguments after the T marker are used
             repeatedly as often as needed; for each reuse, they are taken
             relative to the last previously established tab stop.  When ta is
             called without arguments, all tab stops are cleared.

     tc [glyph]
             Change tab repetition character.  Currently unsupported.

     TE      End a table context.  See TS.

     ti [+|-]width
             Break the output line and indent the next output line by width.
             If a sign is specified, the temporary indentation is calculated
             relative to the current indentation; otherwise, it is absolute.
             The argument follows the syntax of Scaling Widths and the default
             scaling unit is m.

     tkf font minps width1 maxps width2
             Enable track kerning for a font.  Currently ignored.

     tl 'left'center'right'
             Print a title line.  Currently unsupported.

     tm string
             Print to standard error output.  Currently ignored.

     tm1 string
             Print to standard error output, allowing leading blanks.  This is
             a groff extension and currently ignored.

     tmc string
             Print to standard error output without a trailing newline.  This
             is a groff extension and currently ignored.

     tr glyph glyph ...
             Output character translation.  The first glyph in each pair is
             replaced by the second one.  Character escapes can be used; for
             example,

                   tr \(xx\(yy

             replaces all invocations of \(xx with \(yy.

     track font minps width1 maxps width2
             Static letter space tracking.  This is a Heirloom extension and
             currently ignored.

     transchar char ...
             Define transparent characters for sentence-ending.  This is a
             Heirloom extension and currently ignored.

     trf filename
             Output the contents of a file, disallowing invalid characters.
             This is a groff extension and ignored because insecure.

     trimat left top width height
             Set the TrimBox page parameter for PDF generation.  This is a
             Heirloom extension and currently ignored.

     trin glyph glyph ...
             Output character translation, ignored by asciify.  Currently
             unsupported.

     trnt glyph glyph ...
             Output character translation, ignored by \!.  Currently
             unsupported.

     troff   Force troff mode.  This is a groff extension and currently
             ignored.

     TS      Begin a table, which formats input in aligned rows and columns.
             See tbl(7) for a description of the tbl language.

     uf font
             Globally set the underline font.  Currently ignored.

     ul [N]  Underline next N input lines.  Currently ignored.

     unformat divname
             Unformat spaces and tabs in a diversion.  Currently unsupported.

     unwatch macroname
             Disable notification for string or macro.  This is a Heirloom
             extension and currently ignored.

     unwatchn register
             Disable notification for register.  This is a Heirloom extension
             and currently ignored.

     vpt [1 | 0]
             Enable or disable vertical position traps.  This is a groff
             extension and currently ignored.

     vs [[+|-]height]
             Change vertical spacing.  Currently ignored.

     warn flags
             Set warning level.  Currently ignored.

     warnscale si
             Set the scaling indicator used in warnings.  This is a groff
             extension and currently ignored.

     watch macroname
             Notify on change of string or macro.  This is a Heirloom
             extension and currently ignored.

     watchlength maxlength
             On change, report the contents of macros and strings up to the
             specified length.  This is a Heirloom extension and currently
             ignored.

     watchn register
             Notify on change of register.  This is a Heirloom extension and
             currently ignored.

     wh dist [macroname]
             Set a page location trap.  Currently unsupported.

     while condition body
             Repeated execution while a condition is true, with syntax similar
             to if.  Currently implemented with two restrictions: cannot nest,
             and each loop must start and end in the same scope.

     write ["]string
             Write to an open file.  Ignored because insecure.

     writec ["]string
             Write to an open file without appending a newline.  Ignored
             because insecure.

     writem macroname
             Write macro or string to an open file.  Ignored because insecure.

     xflag level
             Set the extension level.  This is a Heirloom extension and
             currently ignored.

   Numerical expressions
     The nr, if, and ie requests accept integer numerical expressions as
     arguments.  These are always evaluated using the C int type; integer
     overflow works the same way as in the C language.  Numbers consist of an
     arbitrary number of digits `0' to `9' prefixed by an optional sign `+' or
     `-'.  Each number may be followed by one optional scaling unit described
     below Scaling Widths.  The following equations hold:

           1i = 6v = 6P = 10m = 10n = 72p = 1000M = 240u = 240
           254c = 100i = 24000u = 24000
           1f = 65536u = 65536

     The following binary operators are implemented.  Unless otherwise stated,
     they behave as in the C language:

     +   addition
     -   subtraction
     *   multiplication
     /   division
     %   remainder of division
     <   less than
     >   greater than
     ==  equal to
     =   equal to, same effect as == (this differs from C)
     <=  less than or equal to
     >=  greater than or equal to
     <>  not equal to (corresponds to C !=; this one is of limited
         portability, it is supported by Heirloom roff, but not by groff)
     &   logical and (corresponds to C &&)
     :   logical or (corresponds to C ||)
     <?  minimum (not available in C)
     >?  maximum (not available in C)

     There is no concept of precedence; evaluation proceeds from left to
     right, except when subexpressions are enclosed in parentheses.  Inside
     parentheses, whitespace is ignored.

ESCAPE SEQUENCE REFERENCE
     The mandoc(1) roff parser recognises the following escape sequences.  In
     mdoc(7) and man(7) documents, using escape sequences is discouraged
     except for those described in the LANGUAGE SYNTAX section above.

     A backslash followed by any character not listed here simply prints that
     character itself.

     \<newline>
             A backslash at the end of an input line can be used to continue
             the logical input line on the next physical input line, joining
             the text on both lines together as if it were on a single input
             line.

     \<space>
             The escape sequence backslash-space (`\ ') is an unpaddable
             space-sized non-breaking space character; see Whitespace and
             mandoc_char(7).

     \!      Embed text up to and including the end of the input line into the
             current diversion or into intermediate output without
             interpreting requests, macros, and escapes.  Currently
             unsupported.

     \"      The rest of the input line is treated as Comments.

     \#      Line continuation with comment.  Discard the rest of the physical
             input line and continue the logical input line on the next
             physical input line, joining the text on both lines together as
             if it were on a single input line.  This is a groff extension.

     \$arg   Macro argument expansion, see de.

     \%      Hyphenation allowed at this point of the word; ignored by
             mandoc(1).

     \&      Non-printing zero-width character, often used for various kinds
             of escaping; see Whitespace, mandoc_char(7), and the "MACRO
             SYNTAX" and "Delimiters" sections in mdoc(7).

     \'      Acute accent special character; use \(aa instead.

     \(cc    Special Characters with two-letter names, see mandoc_char(7).

     \)      Zero-width space transparent to end-of-sentence detection;
             ignored by mandoc(1).

     \*[name]
             Interpolate the string with the name.  For short names, there are
             variants \*c and \*(cc.

             One string is predefined on the roff language level: \*(.T
             expands to the name of the output device, for example ascii,
             utf8, ps, pdf, html, or markdown.

             Macro sets traditionally predefine additional strings which are
             not portable and differ across implementations.  Those supported
             by mandoc(1) are listed in mandoc_char(7).

             Strings can be defined, changed, and deleted with the ds, as, and
             rm requests.

     \,      Left italic correction (groff extension); ignored by mandoc(1).

     \-      Special character "mathematical minus sign"; see mandoc_char(7)
             for details.

     \/      Right italic correction (groff extension); ignored by mandoc(1).

     \:      Breaking the line is allowed at this point of the word without
             inserting a hyphen.

     \?      Embed the text up to the next \? into the current diversion
             without interpreting requests, macros, and escapes.  This is a
             groff extension and currently unsupported.

     \[name]
             Special Characters with names of arbitrary length, see
             mandoc_char(7).

     \^      One-twelfth em half-narrow space character, effectively zero-
             width in mandoc(1).

     \_      Underline special character; use \(ul instead.

     \`      Grave accent special character; use \(ga instead.

     \{      Begin conditional input; see if.

     \|      One-sixth em narrow space character, effectively zero-width in
             mandoc(1).

     \}      End conditional input; see if.

     \~      Paddable non-breaking space character.

     \0      Digit width space character.

     \A'string'
             Anchor definition; ignored by mandoc(1).

     \a      Leader character; ignored by mandoc(1).

     \B'string'
             Interpolate `1' if string conforms to the syntax of Numerical
             expressions explained above or `0' otherwise.

     \b'string'
             Bracket building function; ignored by mandoc(1).

     \C'name'
             Special Characters with names of arbitrary length.

     \c      When encountered at the end of an input text line, the next input
             text line is considered to continue that line, even if there are
             request or macro lines in between.  No whitespace is inserted.

     \D'string'
             Draw graphics function; ignored by mandoc(1).

     \d      Move down by half a line; ignored by mandoc(1).

     \E      Escape character intended to not be interpreted in copy mode.  In
             mandoc(1), it currently does the same as \ itself.

     \e      Backslash special character.

     \F[name]
             Switch font family (groff extension); ignored by mandoc(1).  For
             short names, there are variants \Fc and \F(cc.

     \f[name]
             Switch to the font name, see Font Selection.  For short names,
             there are variants \fc and \f(cc.  An empty name \f[] defaults to
             \fP.

     \g[name]
             Interpolate the format of a number register; ignored by
             mandoc(1).  For short names, there are variants \gc and \g(cc.

     \H'[+|-]number'
             Set the height of the current font; ignored by mandoc(1).

     \h'[|]width'
             Horizontal motion.  If the vertical bar is given, the motion is
             relative to the current indentation.  Otherwise, it is relative
             to the current position.  The default scaling unit is m.

     \k[name]
             Mark horizontal input place in register; ignored by mandoc(1).
             For short names, there are variants \kc and \k(cc.

     \L'number[c]'
             Vertical line drawing function; ignored by mandoc(1).

     \l'width[c]'
             Draw a horizontal line of width using the glyph c.

     \M[name]
             Set fill (background) color (groff extension); ignored by
             mandoc(1).  For short names, there are variants \Mc and \M(cc.

     \m[name]
             Set glyph drawing color (groff extension); ignored by mandoc(1).
             For short names, there are variants \mc and \m(cc.

     \N'number'
             Character number on the current font.

     \n[+|-][name]
             Interpolate the number register name.  For short names, there are
             variants \nc and \n(cc.  If the optional sign is specified, the
             register is first incremented or decremented by the stepsize that
             was specified in the relevant nr request, and the changed value
             is interpolated.

     \Odigit, \O[5arguments]
             Suppress output.  This is a groff extension and currently
             unsupported.  With an argument of 1, 2, 3, or 4, it is ignored.

     \o'string'
             Overstrike, writing all the characters contained in the string to
             the same output position.  In terminal and HTML output modes,
             only the last one of the characters is visible.

     \p      Break the output line at the end of the current word.

     \R'name [+|-]number'
             Set number register; ignored by mandoc(1).

     \r      Move up by one line; ignored by mandoc(1).

     \S'number'
             Slant output; ignored by mandoc(1).

     \s'[+|-]number'
             Change point size; ignored by mandoc(1).  Alternative forms
             \s[+|-]n, \s[+|-]'number', \s[[+|-]number], and \s[+|-][number]
             are also parsed and ignored.

     \t      Horizontal tab; ignored by mandoc(1).

     \u      Move up by half a line; ignored by mandoc(1).

     \V[name]
             Interpolate an environment variable; ignored by mandoc(1).  For
             short names, there are variants \Vc and \V(cc.

     \v'number'
             Vertical motion; ignored by mandoc(1).

     \w'string'
             Interpolate the width of the string.  The mandoc(1)
             implementation assumes that after expansion of user-defined
             strings, the string only contains normal characters, no escape
             sequences, and that each character has a width of 24 basic units.

     \X'string'
             Output string as device control function; ignored in nroff mode
             and by mandoc(1).

     \x'number'
             Extra line space function; ignored by mandoc(1).

     \Y[name]
             Output a string as a device control function; ignored in nroff
             mode and by mandoc(1).  For short names, there are variants \Yc
             and \Y(cc.

     \Z'string'
             Print string with zero width and height; ignored by mandoc(1).

     \z      Output the next character without advancing the cursor position.

COMPATIBILITY
     The mandoc(1) implementation of the roff language is incomplete.  Major
     unimplemented features include:

     -   For security reasons, mandoc(1) never reads or writes external files
         except via so requests with safe relative paths.
     -   There is no automatic hyphenation, no adjustment to the right margin,
         and very limited support for centering; the output is always set
         flush-left.
     -   Support for setting tabulator and leader characters is missing, and
         support for manually changing indentation is limited.
     -   The `u' scaling unit is the default terminal unit.  In traditional
         troff systems, this unit changes depending on the output media.
     -   Width measurements are implemented in a crude way and often yield
         wrong results.  Support for explicit movement requests and escapes is
         limited.
     -   There is no concept of output pages, no support for floats, graphics
         drawing, and picture inclusion; terminal output is always continuous.
     -   Requests regarding color, font families, font sizes, and glyph
         manipulation are ignored.  Font support is very limited.  Kerning is
         not implemented, and no ligatures are produced.
     -   The "'" macro control character does not suppress output line breaks.
     -   Diversions and environments are not implemented, and support for
         traps is very incomplete.
     -   Use of macros is not supported inside tbl(7) code.

     The special semantics of the nS number register is an idiosyncracy of
     OpenBSD manuals and not supported by other mdoc(7) implementations.

SEE ALSO
     mandoc(1), eqn(7), man(7), mandoc_char(7), mdoc(7), tbl(7)

     Joseph F. Ossanna and Brian W. Kernighan, Troff User's Manual, AT&T Bell
     Laboratories, Computing Science Technical Report, 54,
     http://www.kohala.com/start/troff/cstr54.ps, Murray Hill, New Jersey,
     1976 and 1992.

     Joseph F. Ossanna, Brian W. Kernighan, and Gunnar Ritter, Heirloom
     Documentation Tools Nroff/Troff User's Manual,
     http://heirloom.sourceforge.net/doctools/troff.pdf, September 17, 2007.

HISTORY
     The RUNOFF typesetting system, whose input forms the basis for roff, was
     written in MAD and FAP for the CTSS operating system by Jerome E.
     Saltzer in 1964.  Doug McIlroy rewrote it in BCPL in 1969, renaming it
     roff.  Dennis M. Ritchie rewrote McIlroy's roff in PDP-11 assembly for
     Version 1 AT&T UNIX, Joseph F. Ossanna improved roff and renamed it nroff
     for Version 2 AT&T UNIX, then ported nroff to C as troff, which Brian W.
     Kernighan released with Version 7 AT&T UNIX.  In 1989, James Clarke re-
     implemented troff in C++, naming it groff.

AUTHORS
     This roff reference was written by Kristaps Dzonsons <kristaps@bsd.lv>
     and Ingo Schwarze <schwarze@openbsd.org>.

NetBSD 9.99                     January 1, 2019                    NetBSD 9.99