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groff_char(7)       Miscellaneous Information Manual       groff_char(7)

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       groff_char - GNU roff special character and glyph repertoire

Description         top

       The GNU roff typesetting system has a large glyph repertoire
       suitable for production of varied literary, professional,
       technical, and mathematical documents.  groff works with
       characters; an output device renders glyphs.  groff's input
       character set is restricted to that defined by the standards ISO
       Latin-1 (ISO 8859-1) and CCSID “code page” 1047 (an EBCDIC
       arrangement of Latin-1).  For ease of document maintenance in
       UTF-8 environments, it is advisable to use only the Unicode basic
       Latin code points, a subset of all of the foregoing historically
       referred to as US-ASCII, which has only 94 visible, printable
       code points.  In groff, these are termed ordinary characters.
       Often, many more are desired in output.

       AT&T troff in the 1970s faced a similar problem: the available
       typesetter's glyph repertoire differed from that of the computers
       that controlled it.  troff's solution was a form of escape
       sequence known as a special character to access several dozen
       additional glyphs available in the fonts prepared for mounting in
       the phototypesetter.  These glyphs were mapped onto a two-
       character name space for a degree of mnemonic convenience; for
       example, the escape sequence \(aa encoded an acute accent and
       \(sc a section sign.

       groff has lifted historical roff limitations on special character
       name lengths, but recognizes and retains compatibility with the
       historical names.  groff expands the lexicon of glyphs available
       by name and permits users to define their own special character
       escape sequences with the char request.  Special character names
       are groff identifiers; see section “Identifiers” in groff(7).
       Our discussion uses the terms “glyph name” and “special character
       name” interchangeably; we assume no character translations or
       redefinitions.

       This document lists all of the glyph names predefined by groff's
       font description files and presents the systematic notation by
       which it enables access to arbitrary Unicode code points and
       construction of composite glyphs.  Glyphs listed may be
       unavailable, or may vary in appearance, depending on the output
       device and font chosen when the page was formatted.  This page
       was rendered for device utf8 using font R.

       A few escape sequences that are not groff special characters also
       produce glyphs; these exist for syntactical or historical
       reasons.  \', \`, \-, and \_ are translated on input to the
       special character escape sequences \[aa], \[ga], \[-], and \[ul],
       respectively.  Others include \\, \. (backslash-dot), and \e; see
       groff(7).  A small number of special characters represent glyphs
       that are not encoded in Unicode; examples include the baseline
       rule \[ru] and the Bell System logo \[bs].

       In groff, you can test output device support for any character
       (ordinary or special) with the conditional expression operator
       “c”.
              .ie c \[bs] \{Welcome to the \[bs] Bell System;
              did you get the Wehrmacht helmet or the Death Star?\}
              .el No Bell System logo.

       For brevity in the remainder of this document, we shall refer to
       systems conforming to the ISO 646:1991 IRV, ISO 8859, or ISO
       10646 (“Unicode”) character encoding standards as “ISO” systems,
       and those employing IBM code page 1047 as “EBCDIC” systems.  That
       said, EBCDIC systems that support groff are known to also support
       UTF-8.

       While groff accepts eight-bit encoded input, not all such code
       points are valid as input.  On ISO platforms, character codes 0,
       11, 13–31, and 128–159 are invalid.  (This is all C0 and C1
       controls except for SOH through LF [Control+A to Control+J], and
       FF [Control+L].)  On EBCDIC platforms, 0, 8–9, 11, 13–20, 23–31,
       and 48–63 are invalid.  Some of these code points are used by
       groff for internal purposes, which is one reason it does not
       support UTF-8 natively.

   Fundamental character set
       The ordinary characters catalogued above, plus the space, tab,
       newline, and leader (Control+A), form the fundamental character
       set for groff input; anything in the language, even over one
       million code points in Unicode, can be expressed using it.  On
       ISO systems, code points in the range 33–126 comprise a common
       set of printable glyphs in all of the aforementioned ISO
       character encoding standards.  It is this character set and (with
       some noteworthy exceptions) the corresponding glyph repertoire
       for which AT&T troff was implemented.  On EBCDIC systems,
       printable characters are in the range 66–201 and 203–254; those
       without counterparts in the ISO range 33–126 are discussed in the
       next subsection.

       All of the following characters map to glyphs as you would
       expect.

          ┌──────────────────────────────────────────────────────────┐
          │! # $ % & ( ) * + , . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ │
          │A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ ] _ │
          │a b c d e f g h i j k l m n o p q r s t u v w x y z { | } │
       The└─r─e─m─a─i─n─i─n─g──o─r─d─i─n─a─r─y──c─h─a─r─a─c─t─e─r─s──s─u─r─p─r─i─s─e──c─o─m─p─u─t─i─n─g──────────┘
       professionals and others intimately familiar with the ISO
       character encodings.  The developers of AT&T troff chose mappings
       for them that would be useful for typesetting technical
       literature in a broad range of scientific disciplines: Bell Labs
       used the system for preparation of AT&T's patent filings with the
       U.S. government.  Further, the prevailing character encoding
       standard in the 1970s, USAS X3.4-1968 (“ASCII”), deliberately
       supported semantic ambiguity at some code points, and outright
       substitution at several others, to suit the localization demands
       of various national standards bodies.

       The table below presents the seven exceptional code points with
       their typical keycap engravings, their glyph mappings and
       semantics in roff systems, and the escape sequences producing the
       Unicode basic Latin character they replace.  The first, the
       neutral double quote, is a partial exception because it does
       represent itself, but since the roff language also uses it to
       quote macro arguments, groff supports a special character escape
       sequence as an alternative form so that the glyph can be easily
       included in macro arguments without requiring the user to master
       the quoting rules that AT&T troff required in that context.
       (Some requests, like ds, also treat " non-literally.)
       Furthermore, not all of the special character escape sequences
       are portable to AT&T troff and all of its descendants; these
       groff extensions are presented using its special character form
       \[], whereas portable special character escape sequences are
       shown in the traditional \( form.  \- and \e are portable to all
       known troffs.  \e means “the glyph of the current escape
       character”; it therefore can produce unexpected output if the ec
       request is used.  On devices with a limited glyph repertoire,
       glyphs in the “keycap” and “appearance” columns on the same row
       of the table may look identical; except for the neutral double
       quote, this will not be the case on more-capable devices.  Review
       your document using as many different output devices as possible.

      ┌──────────────────────────────────────────────────────────────────┐
      │Keycap   Appearance and meaning   Special character and meaning   │
      ├──────────────────────────────────────────────────────────────────┤
      │"        " neutral double quote   \[dq] neutral double quote      │
      │'        ’ closing single quote   \[aq] neutral apostrophe        │
      │-        - hyphen                 \- or \[-] minus sign/Unix dash │
      │\        (escape character)       \e or \[rs] reverse solidus     │
      │^        ˆ modifier circumflex    \(ha circumflex/caret/“hat”     │
      │`        ‘ opening single quote   \(ga grave accent               │
      │~        ˜ modifier tilde         \(ti tilde                      │
      └──────────────────────────────────────────────────────────────────┘
       The hyphen-minus is a particularly unfortunate case of
       overloading.  Its awkward name in ISO 8859 and later standards
       reflects the many distinguishable purposes to which it had
       already been put by the 1980s, including a hyphen, a minus sign,
       and (alone or in repetition) dashes of varying widths.  For best
       results in roff systems, use the “-” character in input outside
       an escape sequence only to mean a hyphen, as in the phrase “long-
       term”.  For a minus sign in running text or a Unix command-line
       option dash, use \- (or \[-] in groff if you find it helps the
       clarity of the source document).  (Another minus sign, for use in
       mathematical equations, is available as \[mi]).  AT&T troff
       supported em-dashes as \(em, as does groff.

       The special character escape sequence for the apostrophe as a
       neutral single quote is typically needed only in technical
       content; typing words like “can't” and “Anne's” in a natural way
       will render correctly, because in ordinary prose an apostrophe is
       typeset either as a closing single quotation mark or as a neutral
       single quote, depending on the capabilities of the output device.
       By contrast, special character escape sequences should be used
       for quotation marks unless portability to limited or historical
       troff implementations is necessary; on those systems, the input
       convention is to pair the grave accent with the apostrophe for
       single quotes, and to double both characters for double quotes.
       AT&T troff defined no special characters for quotation marks or
       the apostrophe.  Repeated single quotes (‘‘thus’’) will be
       visually distinguishable from double quotes (“thus”) on terminal
       devices, and perhaps on others (depending on the font selected).

       ┌────────────────────────────────────────────────────────────────┐
       │AT&T troff input          recommended groff input               │
       ├────────────────────────────────────────────────────────────────┤
       │A Winter's Tale           A Winter's Tale                       │
       │`U.K. outer quotes'       \[oq]U.K. outer quotes\[cq]           │
       │`U.K. ``inner'' quotes'   \[oq]U.K. \[lq]inner\[rq] quotes\[cq] │
       │``U.S. outer quotes''     \[lq]U.S. outer quotes\[rq]           │
       │``U.S. `inner' quotes''   \[lq]U.S. \[oq]inner\[cq] quotes\[rq] │
       └I─f──y─o─u──f─r─e─q─u─e─n─t─l─y──r─e─q─u─i─r─e──q─u─o─t─a─t─i─o─n──m─a─r─k─s──i─n──y─o─u─r──d─o─c─u─m─e─n─t─,──s─e─e──┘
       if the macro package you're using supplies strings or macros to
       facilitate quotation, or define them yourself (except in man
       pages).

       Using Unicode basic Latin characters to compose boxes and lines
       is ill-advised.  roff systems have special characters for drawing
       horizontal and vertical lines; see subsection “Rules and lines”
       below.  Preprocessors like tbl(1) and pic(1) draw boxes and will
       produce the best possible output for the device, falling back to
       basic Latin glyphs only when necessary.

   Eight-bit encodings and Latin-1 supplement
       ISO 646 is a seven-bit code encoding 128 code points; eight-bit
       codes are twice the size.  ISO 8859-1 and code page 1047
       allocated the additional space to what Unicode calls “C1
       controls” (control characters) and the “Latin-1 supplement”.  The
       C1 controls are neither printable nor usable as groff input.

       Two Latin-1 supplement characters are handled specially on input.
       troff never produces them as output.

       NBSP   encodes a no-break space; it is mapped to \~, the
              adjustable non-breaking space escape sequence.

       SHY    encodes a soft hyphen; it is mapped to \%, the hyphenation
              control escape sequence.

       The remaining characters in the Latin-1 supplement represent
       themselves.  Although they can be specified directly with the
       keyboard on systems configured to use Latin-1 as the character
       encoding, it is more portable, both to other roff systems and to
       UTF-8 environments, to use their special character escape
       sequences, shown below.  The glyph descriptions we use are non-
       standard in some cases, for brevity.

       ¡  \[r!] inverted exclamation mark     Ñ  \[~N] N tilde
       ¢  \[ct] cent sign                     Ò  \[`O] O grave
       £  \[Po] pound sign                    Ó  \['O] O acute
       ¤  \[Cs] currency sign                 Ô  \[^O] O circumflex
       ¥  \[Ye] yen sign                      Õ  \[~O] O tilde
       ¦  \[bb] broken bar                    Ö  \[:O] O dieresis
       §  \[sc] section sign                  ×  \[mu] multiplication sign
       ¨  \[ad] dieresis accent               Ø  \[/O] O slash
       ©  \[co] copyright sign                Ù  \[`U] U grave
       ª  \[Of] feminine ordinal indicator    Ú  \['U] U acute
       «  \[Fo] left double chevron           Û  \[^U] U circumflex
       ¬  \[no] logical not                   Ü  \[:U] U dieresis
       ®  \[rg] registered sign               Ý  \['Y] Y acute
       ¯  \[a-] macron accent                 Þ  \[TP] uppercase thorn
       °  \[de] degree sign                   ß  \[ss] lowercase sharp s
       ±  \[+-] plus-minus                    à  \[`a] a grave
       ²  \[S2] superscript two               á  \['a] a acute
       ³  \[S3] superscript three             â  \[^a] a circumflex
       ´  \[aa] acute accent                  ã  \[~a] a tilde
       µ  \[mc] micro sign                    ä  \[:a] a dieresis
       ¶  \[ps] pilcrow sign                  å  \[oa] a ring
       ·  \[pc] centered period               æ  \[ae] ae ligature
       ¸  \[ac] cedilla accent                ç  \[,c] c cedilla
       ¹  \[S1] superscript one               è  \[`e] e grave
       º  \[Om] masculine ordinal indicator   é  \['e] e acute
       »  \[Fc] right double chevron          ê  \[^e] e circumflex
       ¼  \[14] one quarter symbol            ë  \[:e] e dieresis
       ½  \[12] one half symbol               ì  \[`i] i grave
       ¾  \[34] three quarters symbol         í  \['i] e acute
       ¿  \[r?] inverted question mark        î  \[^i] i circumflex
       À  \[`A] A grave                       ï  \[:i] i dieresis
       Á  \['A] A acute                       ð  \[Sd] lowercase eth
       Â  \[^A] A circumflex                  ñ  \[~n] n tilde
       Ã  \[~A] A tilde                       ò  \[`o] o grave
       Ä  \[:A] A dieresis                    ó  \['o] o acute
       Å  \[oA] A ring                        ô  \[^o] o circumflex
       Æ  \[AE] AE ligature                   õ  \[~o] o tilde
       Ç  \[,C] C cedilla                     ö  \[:o] o dieresis
       È  \[`E] E grave                       ÷  \[di] division sign
       É  \['E] E acute                       ø  \[/o] o slash
       Ê  \[^E] E circumflex                  ù  \[`u] u grave

       Ë  \[:E] E dieresis                    ú  \['u] u acute
       Ì  \[`I] I grave                       û  \[^u] u circumflex
       Í  \['I] I acute                       ü  \[:u] u dieresis
       Î  \[^I] I circumflex                  ý  \['y] y acute
       Ï  \[:I] I dieresis                    þ  \[Tp] lowercase thorn
       Ð  \[-D] uppercase eth                 ÿ  \[:y] y dieresis

   Special character escape forms
       Glyphs that lack a character code in the basic Latin repertoire
       to directly represent them are entered by one of several special
       character escape forms.  Such glyphs can be simple or composite,
       and accessed either by name or numerically by code point.  Code
       points and combining properties are determined by character
       encoding standards, whereas glyph names as used here originated
       in AT&T troff special character escape sequences.  Predefined
       glyph names use only characters in the basic Latin repertoire.

       \(gl   is a special character escape sequence for the glyph with
              the two-character name gl.  This is the original syntax
              form supported by AT&T troff.  The acute accent, \(aa, is
              an example.

       \C'glyph-name'
              is a special character escape sequence for glyph-name,
              which can be of arbitrary length.  The delimiter, shown
              here as a neutral apostrophe, can be any character not
              occurring in glyph-name.  This syntax form was introduced
              in later versions of AT&T device-independent troff.  The
              foregoing acute accent example can be expressed as \C'aa'.

       \[glyph-name]
              is a special character escape sequence for glyph-name,
              which can be of arbitrary length but must not contain a
              closing square bracket “]”.  (No glyph names predefined by
              groff employ “]”.)  The foregoing acute accent example can
              be expressed in groff as \[aa].

       \C'c' and \[c] are not synonyms for the ordinary character “c”,
       but request the special character named “\c”.  For example,
       “\[a]” is not “a”, but rather a special character with the
       internal glyph name (used in font description files and
       diagnostic messages) \a, which is typically undefined.  The only
       such glyph name groff predefines is the minus sign, which can
       therefore be accessed as \C'-' or \[-].

       \[base-char composite-1 composite-2 ... composite-n]
              is a composite glyph.  Glyphs like a lowercase “e” with an
              acute accent, as in the word “café”, can be expressed as
              \[e aa].  See subsection “Accents” below for a table of
              combining glyph names.

       Unicode encodes far more characters than groff has glyph names
       for; special character escape forms based on numerical code
       points enable access to any of them.  Frequently used glyphs or
       glyph combinations can be stored in strings, and new glyph names
       can be created ad hoc with the char request; see groff(7).

       \[unnnn[n[n]]]
              is a Unicode numeric special character escape sequence.
              Any Unicode code point can be accessed with four to six
              hexadecimal digits, with hexadecimal letters accepted in
              uppercase form only.  Thus, \[u02DA] accesses the
              (spacing) ring accent, producing “˚”.

       Unicode code points can be composed as well; when they are, GNU
       troff requires NFD (Normalization Form D), where all Unicode
       glyphs are maximally decomposed.  (Exception: precomposed
       characters in the Latin-1 supplement described above are also
       accepted.  Do not count on this exception remaining in a future
       GNU troff that accepts UTF-8 input directly.)  Thus, GNU troff
       accepts “caf\['e]”, “caf\[e aa]”, and “caf\[u0065_0301]”, as ways
       to input “café”.  (Due to its legacy 8-bit encoding
       compatibility, at present it also accepts “caf\[u00E9]” on ISO
       Latin-1 systems.)

       \[ubase-char[_combining-component]...]
              constructs a composite glyph from Unicode numeric special
              character escape sequences.  The code points of the base
              glyph and the combining components are each expressed in
              hexadecimal, with an underscore (_) separating each
              component.  Thus, \[u006E_0303] produces “ñ”.

       \[charnnn]
              expresses an eight-bit code point where nnn is the code
              point of the character, a decimal number between 0 and 255
              without leading zeroes.  This legacy numeric special
              character escape sequence is used to map characters onto
              glyphs via the trin request in macro files loaded by
              grotty(1).

Glyph tables         top

       In this section, groff's glyph name repertoire is presented in
       tabular form.  The meanings of the columns are as follows.

       Output  shows the glyph as it appears on the device used to
               render this document; although it can have a notably
               different shape on other devices (and is subject to user-
               directed translation and replacement), groff attempts
               reasonable equivalency on all output devices.

       Input   shows the groff character (ordinary or special) that
               normally produces the glyph.  Some code points have
               multiple glyph names.

       Unicode is the code point notation for the glyph or combining
               glyph sequence as described in subsection “Special
               character escape forms” above.  It corresponds to the
               standard notation for Unicode short identifiers such that
               groff's unnnn is equivalent to Unicode's U+nnnn.

       Notes   describes the glyph, elucidating the mnemonic value of
               the glyph name where possible.

               A plus sign “+” indicates that the glyph name appears in
               the AT&T troff user's manual, CSTR #54 (1992 revision).
               When using the AT&T special character syntax \(xx,
               widespread portability can be expected from such names.

               Entries marked with “***” denote glyphs used for
               mathematical purposes.  On typesetting devices, such
               glyphs are typically drawn from a special font (see
               groff_font(5)).  Often, such glyphs lack bold or italic
               style forms or have metrics that look incongruous in
               ordinary prose.  A few which are not uncommon in running
               text have “text variants”, which should work better in
               that context.  Conversely, a handful of glyphs that are
               normally drawn from a text font may be required in
               mathematical equations.  Both sets of exceptions are
               noted in the tables where they appear (“Logical symbols”
               and “Mathematical symbols”).

   Basic Latin
       Apart from basic Latin characters with special mappings,
       described in subsection “Fundamental character set” above, a few
       others in that range have special character glyph names.  These
       were defined for ease of input on non-U.S. keyboards lacking
       keycaps for them, or for symmetry with other special character
       glyph names serving a similar purpose.

       The vertical bar is overloaded; the \[ba] and \[or] escape
       sequences may render differently.  See subsection “Mathematical
       symbols” below for special variants of the plus, minus, and
       equals signs normally drawn from this range.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       "        \[dq]   u0022     neutral double quote
       #        \[sh]   u0023     number sign
       $        \[Do]   u0024     dollar sign
       '        \[aq]   u0027     apostrophe, neutral single quote
       /        \[sl]   u002F     slash, solidus +
       @        \[at]   u0040     at sign
       [        \[lB]   u005B     left square bracket
       \        \[rs]   u005C     reverse solidus
       ]        \[rB]   u005D     right square bracket
       ^        \[ha]   u005E     circumflex, caret, “hat”
       {        \[lC]   u007B     left brace
       |        |       u007C     bar
       |        \[ba]   u007C     bar
       |        \[or]   u007C     bitwise or +
       }        \[rC]   u007D     right brace
       ~        \[ti]   u007E     tilde

   Supplementary Latin letters
       Historically, \[ss] could be considered a ligature of “sz”.  An
       uppercase form is available as \[u1E9E], but in the German
       language it is of specialized use; ß does not normally uppercase-
       transform to it, but rather to “SS”.  “Lowercase f with hook” is
       also used as a function symbol; see subsection “Mathematical
       symbols” below.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       Ð        \[-D]   u00D0     uppercase eth
       ð        \[Sd]   u00F0     lowercase eth
       Þ        \[TP]   u00DE     uppercase thorn
       þ        \[Tp]   u00FE     lowercase thorn
       ß        \[ss]   u00DF     lowercase sharp s
       ı        \[.i]   u0131     i without tittle
       ȷ        \[.j]   u0237     j without tittle
       ƒ        \[Fn]   u0192     lowercase f with hook, function
       Ł        \[/L]   u0141     L with stroke
       ł        \[/l]   u0142     l with stroke
       Ø        \[/O]   u00D8     O with stroke
       ø        \[/o]   u00F8     o with stroke

   Ligatures and digraphs
       Output   Input   Unicode           Notes
       ──────────────────────────────────────────────────────────────────
       ff       \[ff]   u0066_0066        ff ligature +
       fi       \[fi]   u0066_0069        fi ligature +
       fl       \[fl]   u0066_006C        fl ligature +
       ffi      \[Fi]   u0066_0066_0069   ffi ligature +
       ffl      \[Fl]   u0066_0066_006C   ffl ligature +
       Æ        \[AE]   u00C6             AE ligature
       æ        \[ae]   u00E6             ae ligature
       Π       \[OE]   u0152             OE ligature
       œ        \[oe]   u0153             oe ligature
       IJ        \[IJ]   u0132             IJ digraph
       ij        \[ij]   u0133             ij digraph

   Accents
       Normally, the formatting of a special character advances the
       drawing position as an ordinary character does.  groff's
       composite request designates a special character as combining.
       The composite.tmac macro file, loaded automatically by the
       default troffrc, maps the following special characters to the
       combining characters shown below.  The non-combining code point
       in parentheses is used when the special character occurs in
       isolation (compare “caf\[e aa]” and “caf\[aa]e”).

       Output   Input   Unicode         Notes
       ──────────────────────────────────────────────────────────────────
       ˝        \[a"]   u030B (u02DD)   double acute accent
       ¯        \[a-]   u0304 (u00AF)   macron accent
       ˙        \[a.]   u0307 (u02D9)   dot accent
       ^        \[a^]   u0302 (u005E)   circumflex accent
       ´        \[aa]   u0301 (u00B4)   acute accent +
       `        \[ga]   u0300 (u0060)   grave accent +
       ˘        \[ab]   u0306 (u02D8)   breve accent
       ¸        \[ac]   u0327 (u00B8)   cedilla accent
       ¨        \[ad]   u0308 (u00A8)   dieresis accent
       ˇ        \[ah]   u030C (u02C7)   caron accent
       ˚        \[ao]   u030A (u02DA)   ring accent
       ~        \[a~]   u0303 (u007E)   tilde accent
       ˛        \[ho]   u0328 (u02DB)   hook accent

   Accented characters
       All of these glyphs can be composed using combining glyph names
       as described in subsection “Special character escape forms”
       above; the names below are short aliases for convenience.

       Output   Input   Unicode      Notes
       ──────────────────────────────────────────────────────────────────
       Á        \['A]   u0041_0301   A acute
       Ć        \['C]   u0043_0301   C acute
       É        \['E]   u0045_0301   E acute
       Í        \['I]   u0049_0301   I acute
       Ó        \['O]   u004F_0301   O acute
       Ú        \['U]   u0055_0301   U acute
       Ý        \['Y]   u0059_0301   Y acute
       á        \['a]   u0061_0301   a acute
       ć        \['c]   u0063_0301   c acute
       é        \['e]   u0065_0301   e acute
       í        \['i]   u0069_0301   i acute
       ó        \['o]   u006F_0301   o acute
       ú        \['u]   u0075_0301   u acute
       ý        \['y]   u0079_0301   y acute

       Ä        \[:A]   u0041_0308   A dieresis
       Ë        \[:E]   u0045_0308   E dieresis
       Ï        \[:I]   u0049_0308   I dieresis
       Ö        \[:O]   u004F_0308   O dieresis
       Ü        \[:U]   u0055_0308   U dieresis
       Ÿ        \[:Y]   u0059_0308   Y dieresis
       ä        \[:a]   u0061_0308   a dieresis
       ë        \[:e]   u0065_0308   e dieresis
       ï        \[:i]   u0069_0308   i dieresis
       ö        \[:o]   u006F_0308   o dieresis
       ü        \[:u]   u0075_0308   u dieresis
       ÿ        \[:y]   u0079_0308   y dieresis

       Â        \[^A]   u0041_0302   A circumflex
       Ê        \[^E]   u0045_0302   E circumflex
       Î        \[^I]   u0049_0302   I circumflex
       Ô        \[^O]   u004F_0302   O circumflex
       Û        \[^U]   u0055_0302   U circumflex
       â        \[^a]   u0061_0302   a circumflex
       ê        \[^e]   u0065_0302   e circumflex
       î        \[^i]   u0069_0302   i circumflex
       ô        \[^o]   u006F_0302   o circumflex
       û        \[^u]   u0075_0302   u circumflex

       À        \[`A]   u0041_0300   A grave
       È        \[`E]   u0045_0300   E grave
       Ì        \[`I]   u0049_0300   I grave
       Ò        \[`O]   u004F_0300   O grave
       Ù        \[`U]   u0055_0300   U grave
       à        \[`a]   u0061_0300   a grave
       è        \[`e]   u0065_0300   e grave
       ì        \[`i]   u0069_0300   i grave
       ò        \[`o]   u006F_0300   o grave
       ù        \[`u]   u0075_0300   u grave

       Ã        \[~A]   u0041_0303   A tilde
       Ñ        \[~N]   u004E_0303   N tilde
       Õ        \[~O]   u004F_0303   O tilde
       ã        \[~a]   u0061_0303   a tilde
       ñ        \[~n]   u006E_0303   n tilde
       õ        \[~o]   u006F_0303   o tilde

       Š        \[vS]   u0053_030C   S caron
       š        \[vs]   u0073_030C   s caron
       Ž        \[vZ]   u005A_030C   Z caron
       ž        \[vz]   u007A_030C   z caron

       Ç        \[,C]   u0043_0327   C cedilla
       ç        \[,c]   u0063_0327   c cedilla

       Å        \[oA]   u0041_030A   A ring
       å        \[oa]   u0061_030A   a ring

   Quotation marks
       The neutral double quote, often useful when documenting
       programming languages, is also available as a special character
       for convenient embedding in macro arguments; see subsection
       “Fundamental character set” above.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       „        \[Bq]   u201E     low double comma quote
       ‚        \[bq]   u201A     low single comma quote
       “        \[lq]   u201C     left double quote
       ”        \[rq]   u201D     right double quote
       ‘        \[oq]   u2018     single opening (left) quote
       ’        \[cq]   u2019     single closing (right) quote
       '        \[aq]   u0027     apostrophe, neutral single quote
       "        "       u0022     neutral double quote
       "        \[dq]   u0022     neutral double quote
       «        \[Fo]   u00AB     left double chevron
       »        \[Fc]   u00BB     right double chevron
       ‹        \[fo]   u2039     left single chevron
       ›        \[fc]   u203A     right single chevron

   Punctuation
       The Unicode name for U+00B7 is “middle dot”, which is
       unfortunately confusable with the groff mnemonic for the visually
       similar but semantically distinct multiplication dot; see
       subsection “Mathematical symbols” below.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ¡        \[r!]   u00A1     inverted exclamation mark
       ¿        \[r?]   u00BF     inverted question mark
       ·        \[pc]   u00B7     centered period
       —        \[em]   u2014     em-dash +
       –        \[en]   u2013     en-dash
       ‐        \[hy]   u2010     hyphen +

   Brackets
       On typesetting devices, the bracket extensions are font-invariant
       glyphs; that is, they are rendered the same way regardless of
       font (with a drawing escape sequence).  On terminals, they are
       not font-invariant; groff maps them rather arbitrarily to U+23AA
       (“curly bracket extension”).  In AT&T troff, only one glyph was
       available to vertically extend brackets, braces, and parentheses:
       \(bv.

       Not all devices supply bracket pieces that can be piled up with
       \b due to the restrictions of the escape's piling algorithm.  A
       general solution to build brackets out of pieces is the following
       macro:
              .\" Make a pile centered vertically 0.5em above the baseline.
              .\" The first argument is placed at the top.
              .\" The pile is returned in string 'pile'.
              .eo
              .de pile-make
              .  nr pile-wd 0
              .  nr pile-ht 0
              .  ds pile-args
              .
              .  nr pile-# \n[.$]
              .  while \n[pile-#] \{\
              .    nr pile-wd (\n[pile-wd] >? \w'\$[\n[pile-#]]')
              .    nr pile-ht +(\n[rst] - \n[rsb])
              .    as pile-args \v'\n[rsb]u'\"
              .    as pile-args \Z'\$[\n[pile-#]]'\"
              .    as pile-args \v'-\n[rst]u'\"
              .    nr pile-# -1
              .  \}
              .
              .  ds pile \v'(-0.5m + (\n[pile-ht]u / 2u))'\"
              .  as pile \*[pile-args]\"
              .  as pile \v'((\n[pile-ht]u / 2u) + 0.5m)'\"
              .  as pile \h'\n[pile-wd]u'\"
              ..
              .ec

       Another complication is the fact that some glyphs which represent
       bracket pieces in AT&T troff can be used for other mathematical
       symbols as well, for example \(lf and \(rf, which provide the
       floor operator.  Some output devices, such as dvi, don't unify
       such glyphs.  For this reason, the glyphs \[lf], \[rf], \[lc],
       and \[rc] are not unified with similar-looking bracket pieces.
       In groff, only glyphs with long names are guaranteed to pile up
       correctly for all devices—provided those glyphs are available.

       Output   Input               Unicode   Notes
       ──────────────────────────────────────────────────────────────────────
       [        [                   u005B     left square bracket
       [        \[lB]               u005B     left square bracket
       ]        ]                   u005D     right square bracket
       ]        \[rB]               u005D     right square bracket
       {        {                   u007B     left brace
       {        \[lC]               u007B     left brace
       }        }                   u007D     right brace
       }        \[rC]               u007D     right brace
       ⟨        \[la]               u27E8     left angle bracket
       ⟩        \[ra]               u27E9     right angle bracket
       ⎪        \[bv]               u23AA     brace vertical extension + ***
       ⎪        \[braceex]          u23AA     brace vertical extension

       ⎡        \[bracketlefttp]    u23A1     left square bracket top
       ⎢        \[bracketleftex]    u23A2     left square bracket extension
       ⎣        \[bracketleftbt]    u23A3     left square bracket bottom

       ⎤        \[bracketrighttp]   u23A4     right square bracket top
       ⎥        \[bracketrightex]   u23A5     right square bracket extension
       ⎦        \[bracketrightbt]   u23A6     right square bracket bottom

       ⎧        \[lt]               u23A7     left brace top +
       ⎨        \[lk]               u23A8     left brace middle +

       ⎩        \[lb]               u23A9     left brace bottom +
       ⎧        \[bracelefttp]      u23A7     left brace top
       ⎨        \[braceleftmid]     u23A8     left brace middle
       ⎩        \[braceleftbt]      u23A9     left brace bottom
       ⎪        \[braceleftex]      u23AA     left brace extension

       ⎫        \[rt]               u23AB     right brace top +
       ⎬        \[rk]               u23AC     right brace middle +
       ⎭        \[rb]               u23AD     right brace bottom +
       ⎫        \[bracerighttp]     u23AB     right brace top
       ⎬        \[bracerightmid]    u23AC     right brace middle
       ⎭        \[bracerightbt]     u23AD     right brace bottom
       ⎪        \[bracerightex]     u23AA     right brace extension

       ⎛        \[parenlefttp]      u239B     left parenthesis top
       ⎜        \[parenleftex]      u239C     left parenthesis extension
       ⎝        \[parenleftbt]      u239D     left parenthesis bottom
       ⎞        \[parenrighttp]     u239E     right parenthesis top
       ⎟        \[parenrightex]     u239F     right parenthesis extension
       ⎠        \[parenrightbt]     u23A0     right parenthesis bottom

   Arrows
       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ←        \[<-]   u2190     horizontal arrow left +
       →        \[->]   u2192     horizontal arrow right +
       ↔        \[<>]   u2194     bidirectional horizontal arrow
       ↓        \[da]   u2193     vertical arrow down +
       ↑        \[ua]   u2191     vertical arrow up +
       ↕        \[va]   u2195     bidirectional vertical arrow
       ⇐        \[lA]   u21D0     horizontal double arrow left
       ⇒        \[rA]   u21D2     horizontal double arrow right
       ⇔        \[hA]   u21D4     bidirectional horizontal double arrow
       ⇓        \[dA]   u21D3     vertical double arrow down
       ⇑        \[uA]   u21D1     vertical double arrow up
       ⇕        \[vA]   u21D5     bidirectional vertical double arrow
       ⎯        \[an]   u23AF     horizontal arrow extension

   Rules and lines
       On typesetting devices, the font-invariant glyphs (see subsection
       “Brackets” above) \[br], \[ul], and \[rn] form corners when
       adjacent; they can be used to build boxes.  On terminal devices,
       they are mapped as shown in the table.  The Unicode-derived names
       of these three glyphs are approximations.

       The input character _ always accesses the underscore glyph in a
       font; \[ul], by contrast, may be font-invariant on typesetting
       devices.

       The baseline rule \[ru] is a font-invariant glyph, namely a rule
       of one-half em.

       In AT&T troff, \[rn] also served as a one en extension of the
       square root symbol.  groff favors \[radicalex] for this purpose;
       see subsection “Mathematical symbols” below.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       |        |       u007C     bar
       |        \[ba]   u007C     bar
       │        \[br]   u2502     box rule +
       _        _       u005F     underscore, low line +
       _        \[ul]   ---       underrule +
       ‾        \[rn]   u203E     overline +
       _        \[ru]   ---       baseline rule +
       ¦        \[bb]   u00A6     broken bar
       /        /       u002F     slash, solidus +
       /        \[sl]   u002F     slash, solidus +
       \        \[rs]   u005C     reverse solidus

   Text markers
       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ○        \[ci]   u25CB     circle +

       •        \[bu]   u2022     bullet +
       †        \[dg]   u2020     dagger +
       ‡        \[dd]   u2021     double dagger +
       ◊        \[lz]   u25CA     lozenge, diamond
       □        \[sq]   u25A1     square +
       ¶        \[ps]   u00B6     pilcrow sign
       §        \[sc]   u00A7     section sign +
       ☜        \[lh]   u261C     hand pointing left +
       ☞        \[rh]   u261E     hand pointing right +
       @        @       u0040     at sign
       @        \[at]   u0040     at sign
       #        #       u0023     number sign
       #        \[sh]   u0023     number sign
       ↵        \[CR]   u21B5     carriage return
       ✓        \[OK]   u2713     check mark

   Legal symbols
       The Bell System logo is not supported in groff.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ©        \[co]   u00A9     copyright sign +
       ®        \[rg]   u00AE     registered sign +
       ™        \[tm]   u2122     trade mark sign
                \[bs]   ---       Bell System logo +

   Currency symbols
       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       $        $       u0024     dollar sign
       $        \[Do]   u0024     dollar sign
       ¢        \[ct]   u00A2     cent sign +
       €        \[eu]   u20AC     Euro sign
       €        \[Eu]   u20AC     variant Euro sign
       ¥        \[Ye]   u00A5     yen sign
       £        \[Po]   u00A3     pound sign
       ¤        \[Cs]   u00A4     currency sign

   Units
       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       °        \[de]   u00B0     degree sign +
       ‰        \[%0]   u2030     per thousand, per mille sign
       ′        \[fm]   u2032     arc minute sign, foot mark +
       ″        \[sd]   u2033     arc second sign
       µ        \[mc]   u00B5     micro sign
       ª        \[Of]   u00AA     feminine ordinal indicator
       º        \[Om]   u00BA     masculine ordinal indicator

   Logical symbols
       The variants of the not sign may differ in appearance or spacing
       depending on the device and font selected.  Unicode does not
       encode a discrete “bitwise or” sign: on typesetting devices, it
       is drawn shorter than the bar, about the same height as a capital
       letter.  Terminal devices unify \[ba] and \[or].

       Output   Input    Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ∧        \[AN]    u2227     logical and
       ∨        \[OR]    u2228     logical or
       ¬        \[no]    u00AC     logical not + ***
       ¬        \[tno]   u00AC     text variant of \[no]
       ∃        \[te]    u2203     there exists
       ∀        \[fa]    u2200     for all
       ∋        \[st]    u220B     such that
       ∴        \[3d]    u2234     therefore
       ∴        \[tf]    u2234     therefore
       |        |        u007C     bar
       |        \[or]    u007C     bitwise or +

   Mathematical symbols
       \[Fn] also appears in subsection “Supplementary Latin letters”
       above.  Observe the two varieties of the plus-minus,
       multiplication, and division signs; \[+-], \[mu], and \[di] are
       normally drawn from the special font, but have text font
       variants.  Also be aware of three glyphs available in special
       font variants that are normally drawn from text fonts: the plus,
       minus, and equals signs.  These variants may differ in appearance
       or spacing depending on the device and font selected.

       In AT&T troff, \(rn (“root en extender”) served as the horizontal
       extension of the radical (square root) sign, \(sr, and was drawn
       at the maximum height of the typeface's bounding box; this
       enabled the special character to double as an overline (see
       subsection “Rules and lines” above).  A contemporary font's
       radical sign might not ascend to such an extreme.  In groff, you
       can instead use \[radicalex] to continue the radical sign \[sr];
       these special characters are intended for use with text fonts.
       \[sqrt] and \[sqrtex] are their counterparts with mathematical
       spacing.

       Output   Input          Unicode      Notes
       ─────────────────────────────────────────────────────────────────────
       ½        \[12]          u00BD        one half symbol +
       ¼        \[14]          u00BC        one quarter symbol +
       ¾        \[34]          u00BE        three quarters symbol +
       ⅛        \[18]          u215B        one eighth symbol
       ⅜        \[38]          u215C        three eighths symbol
       ⅝        \[58]          u215D        five eighths symbol
       ⅞        \[78]          u215E        seven eighths symbol
       ¹        \[S1]          u00B9        superscript one
       ²        \[S2]          u00B2        superscript two
       ³        \[S3]          u00B3        superscript three

       +        +              u002B        plus
       +        \[pl]          u002B        special variant of plus + ***
       -        \[-]           u002D        minus
       −        \[mi]          u2212        special variant of minus + ***
       ∓        \[-+]          u2213        minus-plus
       ±        \[+-]          u00B1        plus-minus + ***
       ±        \[t+-]         u00B1        text variant of \[+-]
       ⋅        \[md]          u22C5        multiplication dot
       ×        \[mu]          u00D7        multiplication sign + ***
       ×        \[tmu]         u00D7        text variant of \[mu]
       ⊗        \[c*]          u2297        circled times
       ⊕        \[c+]          u2295        circled plus
       ÷        \[di]          u00F7        division sign + ***
       ÷        \[tdi]         u00F7        text variant of \[di]
       ⁄        \[f/]          u2044        fraction slash
       *        *              u002A        asterisk
       ∗        \[**]          u2217        mathematical asterisk +

       ≤        \[<=]          u2264        less than or equal to +
       ≥        \[>=]          u2265        greater than or equal to +
       ≪        \[<<]          u226A        much less than
       ≫        \[>>]          u226B        much greater than
       =        =              u003D        equals
       =        \[eq]          u003D        special variant of equals + ***
       ≠        \[!=]          u003D_0338   not equals +
       ≡        \[==]          u2261        equivalent +
       ≢        \[ne]          u2261_0338   not equivalent
       ≅        \[=~]          u2245        approximately equal to
       ≃        \[|=]          u2243        asymptotically equal to +
       ~        \[ti]          u007E        tilde +
       ∼        \[ap]          u223C        similar to, tilde operator +
       ≈        \[~~]          u2248        almost equal to
       ≈        \[~=]          u2248        almost equal to
       ∝        \[pt]          u221D        proportional to +

       ∅        \[es]          u2205        empty set +
       ∈        \[mo]          u2208        element of a set +
       ∉        \[nm]          u2208_0338   not element of set
       ⊂        \[sb]          u2282        proper subset +
       ⊄        \[nb]          u2282_0338   not subset
       ⊃        \[sp]          u2283        proper superset +
       ⊅        \[nc]          u2283_0338   not superset
       ⊆        \[ib]          u2286        subset or equal +
       ⊇        \[ip]          u2287        superset or equal +
       ∩        \[ca]          u2229        intersection, cap +

       ∪        \[cu]          u222A        union, cup +

       ∠        \[/_]          u2220        angle
       ⊥        \[pp]          u22A5        perpendicular
       ∫        \[is]          u222B        integral +
       ∫        \[integral]    u222B        integral ***
       ∑        \[sum]         u2211        summation ***
       ∏        \[product]     u220F        product ***
       ∐        \[coproduct]   u2210        coproduct ***
       ∇        \[gr]          u2207        gradient +
       √        \[sr]          u221A        radical sign, square root +
       ‾        \[rn]          u203E        overline +
                \[radicalex]   ---          radical extension
       √        \[sqrt]        u221A        radical sign, square root ***
                \[sqrtex]      ---          radical extension ***

       ⌈        \[lc]          u2308        left ceiling +
       ⌉        \[rc]          u2309        right ceiling +
       ⌊        \[lf]          u230A        left floor +
       ⌋        \[rf]          u230B        right floor +

       ∞        \[if]          u221E        infinity +
       ℵ        \[Ah]          u2135        aleph symbol
       ƒ        \[Fn]          u0192        lowercase f with hook, function
       ℑ        \[Im]          u2111        blackletter I, imaginary part
       ℜ        \[Re]          u211C        blackletter R, real part
       ℘        \[wp]          u2118        Weierstrass p
       ∂        \[pd]          u2202        partial differential
       ℏ        \[-h]          u210F        h bar
       ℏ        \[hbar]        u210F        h bar

   Greek glyphs
       These glyphs are intended for technical use, not for typesetting
       Greek language text; normally, the uppercase letters have upright
       shape, and the lowercase ones are slanted.

       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       Α        \[*A]   u0391     uppercase alpha +
       Β        \[*B]   u0392     uppercase beta +
       Γ        \[*G]   u0393     uppercase gamma +
       Δ        \[*D]   u0394     uppercase delta +
       Ε        \[*E]   u0395     uppercase epsilon +
       Ζ        \[*Z]   u0396     uppercase zeta +
       Η        \[*Y]   u0397     uppercase eta +
       Θ        \[*H]   u0398     uppercase theta +
       Ι        \[*I]   u0399     uppercase iota +
       Κ        \[*K]   u039A     uppercase kappa +
       Λ        \[*L]   u039B     uppercase lambda +
       Μ        \[*M]   u039C     uppercase mu +
       Ν        \[*N]   u039D     uppercase nu +
       Ξ        \[*C]   u039E     uppercase xi +
       Ο        \[*O]   u039F     uppercase omicron +
       Π        \[*P]   u03A0     uppercase pi +
       Ρ        \[*R]   u03A1     uppercase rho +
       Σ        \[*S]   u03A3     uppercase sigma +
       Τ        \[*T]   u03A4     uppercase tau +
       Υ        \[*U]   u03A5     uppercase upsilon +
       Φ        \[*F]   u03A6     uppercase phi +
       Χ        \[*X]   u03A7     uppercase chi +
       Ψ        \[*Q]   u03A8     uppercase psi +
       Ω        \[*W]   u03A9     uppercase omega +

       α        \[*a]   u03B1     lowercase alpha +
       β        \[*b]   u03B2     lowercase beta +
       γ        \[*g]   u03B3     lowercase gamma +
       δ        \[*d]   u03B4     lowercase delta +
       ε        \[*e]   u03B5     lowercase epsilon +
       ζ        \[*z]   u03B6     lowercase zeta +
       η        \[*y]   u03B7     lowercase eta +
       θ        \[*h]   u03B8     lowercase theta +
       ι        \[*i]   u03B9     lowercase iota +
       κ        \[*k]   u03BA     lowercase kappa +
       λ        \[*l]   u03BB     lowercase lambda +

       μ        \[*m]   u03BC     lowercase mu +
       ν        \[*n]   u03BD     lowercase nu +
       ξ        \[*c]   u03BE     lowercase xi +
       ο        \[*o]   u03BF     lowercase omicron +
       π        \[*p]   u03C0     lowercase pi +
       ρ        \[*r]   u03C1     lowercase rho +
       σ        \[*s]   u03C3     lowercase sigma +
       τ        \[*t]   u03C4     lowercase tau +
       υ        \[*u]   u03C5     lowercase upsilon +
       ϕ        \[*f]   u03D5     lowercase phi +
       χ        \[*x]   u03C7     lowercase chi +
       ψ        \[*q]   u03C8     lowercase psi +
       ω        \[*w]   u03C9     lowercase omega +

       ϵ        \[+e]   u03F5     variant epsilon (lunate)
       ϑ        \[+h]   u03D1     variant theta (cursive form)
       ϖ        \[+p]   u03D6     variant pi (similar to omega)
       φ        \[+f]   u03C6     variant phi (curly shape)
       ς        \[ts]   u03C2     terminal lowercase sigma +

   Playing card symbols
       Output   Input   Unicode   Notes
       ──────────────────────────────────────────────────────────────────
       ♣        \[CL]   u2663     solid club suit
       ♠        \[SP]   u2660     solid spade suit
       ♥        \[HE]   u2665     solid heart suit
       ♦        \[DI]   u2666     solid diamond suit

History         top

       A consideration of the typefaces originally available to AT&T
       nroff and troff illuminates many conventions that one might
       regard as idiosyncratic fifty years afterward.  (See section
       “History” of roff(7) for more context.)  The face used by the
       Teletype Model 37 terminals of the Murray Hill Unix Room was
       based on ASCII, but assigned multiple meanings to several code
       points, as suggested by that standard.  Decimal 34 (") served as
       a dieresis accent and neutral double quotation mark; decimal 39
       (') as an acute accent, apostrophe, and closing (right) single
       quotation mark; decimal 45 (-) as a hyphen and a minus sign;
       decimal 94 (^) as a circumflex accent and caret; decimal 96 (`)
       as a grave accent and opening (left) single quotation mark; and
       decimal 126 (~) as a tilde accent and (with a half-line motion)
       swung dash.  The Model 37 bore an optional extended character set
       offering upright Greek letters and several mathematical symbols;
       these were documented as early as the kbd(VII) man page of the
       (First Edition) Unix Programmer's Manual.

       At the time Graphic Systems delivered the C/A/T phototypesetter
       to AT&T, the ASCII character set was not considered a standard
       basis for a glyph repertoire by traditional typographers.  In the
       stock Times roman, italic, and bold styles available, several
       ASCII characters were not present at all, nor was most of the
       Teletype's extended character set.  AT&T commissioned a “special”
       font to ensure no loss of repertoire.

       A representation of the coverage of the C/A/T's text fonts
       follows.  The glyph resembling an underscore is a baseline rule,
       and that resembling a vertical line is a box rule.  In italics,
       the box rule was not slanted.  We also observe that the hyphen
       and minus sign were already “de-unified” by the fonts provided; a
       decision whither to map an input “-” therefore had to be taken.

             ┌────────────────────────────────────────────────────┐
             │A B C D E F G H I J K L M N O P Q R S T U V W X Y Z │
             │a b c d e f g h i j k l m n o p q r s t u v w x y z │
             │0 1 2 3 4 5 6 7 8 9 fi fl ffi ffl                   │
             │! $ % & ( ) ‘ ’ * + - . , / : ; = ? [ ] │           │
             │• □ — ‐ _ ¼ ½ ¾ ° † ′ ¢ ® ©                         │
             └────────────────────────────────────────────────────┘
       The special font supplied the missing ASCII and Teletype extended
       glyphs, among several others.  The plus, minus, and equals signs
       appeared in the special font despite availability in text fonts
       “to insulate the appearance of equations from the choice of
       standard [read: text] fonts”—a priority since troff was turned to
       the task of mathematical typesetting as soon as it was developed.

       We note that AT&T took the opportunity to de-unify the
       apostrophe/right single quotation mark from the acute accent (a
       choice ISO later duplicated in its 8859 series of standards).  A
       slash intended to be mirror-symmetric with the backslash was also
       included, as was the Bell System logo; we do not attempt to
       depict the latter.

          ┌─────────────────────────────────────────────────────────┐
          │α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ ς τ υ ϕ χ ψ ω        │
          │Γ Δ Θ Λ Ξ Π Σ Υ Φ Ψ Ω                                    │
          │" ´ \ ^ _ ` ~ / < > { } # @ + − = ∗                      │
          │≥ ≤ ≡ ≈ ∼ ≠ ↑ ↓ ← → × ÷ ± ∞ ∂ ∇ ¬ ∫ ∝ √  ∪ ∩ ⊂ ⊃ ⊆ ⊇ ∅ ∈ │
          │§ ‡ ☜ ☞ | ○ ⎧ ⎩ ⎫ ⎭ ⎨ ⎬ ⎪ ⌊ ⌋ ⌈ ⌉                        │
          └─────────────────────────────────────────────────────────┘
       One ASCII character as rendered by the Model 37 was apparently
       abandoned.  That device printed decimal 124 (|) as a broken
       vertical line, like Unicode U+00A6 (¦).  No equivalent was
       available on the C/A/T; the box rule \[br], brace vertical
       extension \[bv], and “or” operator \[or] were used as
       contextually appropriate.

       Devices supported by AT&T device-independent troff exhibited some
       differences in glyph detail.  For example, on the Autologic APS-5
       phototypesetter, the square \(sq became filled in the Times bold
       face.

Files         top

       The files below are loaded automatically by the default troffrc.

       /usr/local/share/groff/1.23.0/tmac/composite.tmac
              assigns alternate mappings for identifiers after the first
              in a composite special character escape sequence.  See
              subsection “Accents” above.

       /usr/local/share/groff/1.23.0/tmac/fallbacks.tmac
              defines fallback mappings for Unicode code points such as
              the increment sign (U+2206) and upper- and lowercase Roman
              numerals.

Authors         top

       This document was written by James Clark ⟨jjc@jclark.com⟩, with
       additions by Werner Lemberg ⟨wl@gnu.org⟩ and Bernd Warken
       ⟨groff-bernd.warken-72@web.de⟩, revised to use tbl(1) by Eric S.
       Raymond ⟨esr@thyrsus.com⟩, and largely rewritten by G. Branden
       Robinson ⟨g.branden.robinson@gmail.com⟩.

See also         top

       Groff: The GNU Implementation of troff, by Trent A. Fisher and
       Werner Lemberg, is the primary groff manual.  Section “Using
       Symbols” may be of particular note.  You can browse it
       interactively with “info '(groff) Using Symbols'”.

       “An extension to the troff character set for Europe”, E.G.
       Keizer, K.J. Simonsen, J. Akkerhuis; EUUG Newsletter, Volume 9,
       No. 2, Summer 1989

       The Unicode Standard ⟨http://www.unicode.org⟩

       “7-bit Character Sets” 
       ⟨https://www.aivosto.com/articles/charsets-7bit.html⟩ by Tuomas
       Salste documents the inherent ambiguity and configurable code
       points of the ASCII encoding standard.

       “Nroff/Troff User's Manual” by Joseph F. Ossanna, 1976, AT&T Bell
       Laboratories Computing Science Technical Report No. 54, features
       two tables that throw light on the glyph repertoire available to
       “typesetter roff” when it was first written.  Be careful of re-
       typeset versions of this document that can be found on the
       Internet.  Some do not accurately represent the original
       document: several glyphs are obviously missing.  More subtly,
       lowercase Greek letters are rendered upright, not slanted as they
       appeared in the C/A/T's special font and as expected by troff
       users.

       groff_rfc1345(7) describes an alternative set of special
       character glyph names, which extends and in some cases overrides
       the definitions listed above.

       groff(1), troff(1), groff(7)

COLOPHON         top

       This page is part of the groff (GNU troff) project.  Information
       about the project can be found at 
       ⟨http://www.gnu.org/software/groff/⟩.  If you have a bug report
       for this manual page, see ⟨http://www.gnu.org/software/groff/⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://git.savannah.gnu.org/git/groff.git⟩ on 2023-06-23.  (At
       that time, the date of the most recent commit that was found in
       the repository was 2023-06-23.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

groff 1.23.0.rc4.250-1b2b6-dirt2y2 June 2023                 groff_char(7)