This is groff, produced by makeinfo version 4.3d from ./groff.texinfo.

This manual documents GNU `troff' version 1.19.

   Copyright (C) 1994-2000, 2001, 2002, 2003 Free Software Foundation,
Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.1 or any later version published by the Free Software
     Foundation; with no Invariant Sections, with the Front-Cover texts
     being `A GNU Manual," and with the Back-Cover Texts as in (a)
     below.  A copy of the license is included in the section entitled
     `GNU Free Documentation License."

     (a) The FSF's Back-Cover Text is: `You have freedom to copy and
     modify this GNU Manual, like GNU software.  Copies published by
     the Free Software Foundation raise funds for GNU development."
   
INFO-DIR-SECTION Typesetting
START-INFO-DIR-ENTRY
* Groff: (groff).               The GNU troff document formatting system.
END-INFO-DIR-ENTRY


File: groff,  Node: Concept Index,  Prev: Program and File Index,  Up: Top

Concept Index
*************

* Menu:

* ", at end of sentence <1>:             Using Symbols.
* ", at end of sentence:                 Sentences.
* ", in a macro argument:                Request and Macro Arguments.
* %, as delimiter:                       Escapes.
* &, as delimiter:                       Escapes.
* ', as a comment:                       Comments.
* ', at end of sentence <1>:             Using Symbols.
* ', at end of sentence:                 Sentences.
* ', delimiting arguments:               Escapes.
* (, as delimiter:                       Escapes.
* (, starting a two-character identifier <1>: Escapes.
* (, starting a two-character identifier: Identifiers.
* ), as delimiter:                       Escapes.
* ), at end of sentence <1>:             Using Symbols.
* ), at end of sentence:                 Sentences.
* *, as delimiter:                       Escapes.
* *, at end of sentence <1>:             Using Symbols.
* *, at end of sentence:                 Sentences.
* +, and page motion:                    Expressions.
* +, as delimiter:                       Escapes.
* -, and page motion:                    Expressions.
* -, as delimiter:                       Escapes.
* ., as delimiter:                       Escapes.
* .h register, difference to nl:         Diversions.
* .ps register, in comparison with .psr: Fractional Type Sizes.
* .s register, in comparison with .sr:   Fractional Type Sizes.
* .S register, Plan 9 alias for .tabs:   Tabs and Fields.
* .t register, and diversions:           Diversion Traps.
* .tabs register, Plan 9 alias (.S):     Tabs and Fields.
* .V register, and vs:                   Changing Type Sizes.
* /, as delimiter:                       Escapes.
* 8-bit input:                           Font File Format.
* <, as delimiter:                       Escapes.
* <colon>, as delimiter:                 Escapes.
* =, as delimiter:                       Escapes.
* >, as delimiter:                       Escapes.
* [, macro names starting with, and refer: Identifiers.
* [, starting an identifier <1>:         Escapes.
* [, starting an identifier:             Identifiers.
* \!, and output:                        Diversions.
* \!, and trnt:                          Character Translations.
* \!, in top-level diversion:            Diversions.
* \!, incompatibilities with AT&T troff: Implementation Differences.
* \!, used as delimiter:                 Escapes.
* \$, when reading text for a macro:     Copy-in Mode.
* \%, and translations:                  Character Translations.
* \%, following \X or \Y:                Manipulating Hyphenation.
* \%, in \X:                             Postprocessor Access.
* \%, incompatibilities with AT&T troff: Implementation Differences.
* \%, used as delimiter:                 Escapes.
* \&, and glyph definitions:             Using Symbols.
* \&, and translations:                  Character Translations.
* \&, at end of sentence:                Sentences.
* \&, escaping control characters:       Requests.
* \&, in \X:                             Postprocessor Access.
* \&, incompatibilities with AT&T troff: Implementation Differences.
* \&, used as delimiter:                 Escapes.
* \', and translations:                  Character Translations.
* \', incompatibilities with AT&T troff: Implementation Differences.
* \', used as delimiter:                 Escapes.
* \(, and translations:                  Character Translations.
* \), in \X:                             Postprocessor Access.
* \), used as delimiter:                 Escapes.
* \*, and warnings:                      Warnings.
* \*, incompatibilities with AT&T troff: Implementation Differences.
* \*, when reading text for a macro:     Copy-in Mode.
* \, disabling (eo):                     Character Translations.
* \,, used as delimiter:                 Escapes.
* \-, and translations:                  Character Translations.
* \-, incompatibilities with AT&T troff: Implementation Differences.
* \-, used as delimiter:                 Escapes.
* \/, used as delimiter:                 Escapes.
* \0, used as delimiter:                 Escapes.
* \<colon>, in \X:                       Postprocessor Access.
* \<colon>, used as delimiter:           Escapes.
* \<RET>, when reading text for a macro: Copy-in Mode.
* \<SP>, difference to \~:               Request and Macro Arguments.
* \<SP>, incompatibilities with AT&T troff: Implementation Differences.
* \<SP>, used as delimiter:              Escapes.
* \?, in top-level diversion:            Diversions.
* \?, incompatibilities with AT&T troff: Implementation Differences.
* \?, used as delimiter:                 Escapes.
* \@, used as delimiter:                 Escapes.
* \[, and translations:                  Character Translations.
* \\, when reading text for a macro:     Copy-in Mode.
* \^, incompatibilities with AT&T troff: Implementation Differences.
* \^, used as delimiter:                 Escapes.
* \_, and translations:                  Character Translations.
* \_, incompatibilities with AT&T troff: Implementation Differences.
* \_, used as delimiter:                 Escapes.
* \`, and translations:                  Character Translations.
* \`, incompatibilities with AT&T troff: Implementation Differences.
* \`, used as delimiter:                 Escapes.
* \A, allowed delimiters:                Escapes.
* \a, and translations:                  Character Translations.
* \A, incompatibilities with AT&T troff: Implementation Differences.
* \a, used as delimiter:                 Escapes.
* \B, allowed delimiters:                Escapes.
* \b, limitations:                       Drawing Requests.
* \b, possible quote characters:         Escapes.
* \C, allowed delimiters:                Escapes.
* \c, and fill mode:                     Line Control.
* \c, and no-fill mode:                  Line Control.
* \C, and translations:                  Character Translations.
* \c, incompatibilities with AT&T troff: Implementation Differences.
* \c, used as delimiter:                 Escapes.
* \D'f ...' and horizontal resolution:   Drawing Requests.
* \D, allowed delimiters:                Escapes.
* \d, used as delimiter:                 Escapes.
* \e, and glyph definitions:             Using Symbols.
* \e, and translations:                  Character Translations.
* \e, incompatibilities with AT&T troff: Implementation Differences.
* \e, used as delimiter:                 Escapes.
* \E, used as delimiter:                 Escapes.
* \e, used as delimiter:                 Escapes.
* \F, and changing fonts:                Changing Fonts.
* \F, and font positions:                Font Positions.
* \f, and font translations:             Changing Fonts.
* \f, incompatibilities with AT&T troff: Implementation Differences.
* \H, allowed delimiters:                Escapes.
* \h, allowed delimiters:                Escapes.
* \H, incompatibilities with AT&T troff: Implementation Differences.
* \H, using + and -:                     Expressions.
* \H, with fractional type sizes:        Fractional Type Sizes.
* \L, allowed delimiters:                Escapes.
* \l, allowed delimiters:                Escapes.
* \L, and glyph definitions:             Using Symbols.
* \l, and glyph definitions:             Using Symbols.
* \N, allowed delimiters:                Escapes.
* \N, and translations:                  Character Translations.
* \n, and warnings:                      Warnings.
* \n, incompatibilities with AT&T troff: Implementation Differences.
* \n, when reading text for a macro:     Copy-in Mode.
* \o, possible quote characters:         Escapes.
* \p, used as delimiter:                 Escapes.
* \R, after \c:                          Line Control.
* \R, allowed delimiters:                Escapes.
* \R, and warnings:                      Warnings.
* \R, difference to nr:                  Auto-increment.
* \r, used as delimiter:                 Escapes.
* \R, using + and -:                     Expressions.
* \S, allowed delimiters:                Escapes.
* \s, allowed delimiters:                Escapes.
* \S, incompatibilities with AT&T troff: Implementation Differences.
* \s, incompatibilities with AT&T troff: Implementation Differences.
* \s, using + and -:                     Expressions.
* \s, with fractional type sizes:        Fractional Type Sizes.
* \t, and translations:                  Character Translations.
* \t, and warnings:                      Warnings.
* \t, used as delimiter:                 Escapes.
* \u, used as delimiter:                 Escapes.
* \v, allowed delimiters:                Escapes.
* \v, internal representation:           Gtroff Internals.
* \w, allowed delimiters:                Escapes.
* \x, allowed delimiters:                Escapes.
* \X, and special characters:            Postprocessor Access.
* \X, followed by \%:                    Manipulating Hyphenation.
* \X, possible quote characters:         Escapes.
* \Y, followed by \%:                    Manipulating Hyphenation.
* \Z, allowed delimiters:                Escapes.
* \{, incompatibilities with AT&T troff: Implementation Differences.
* \{, used as delimiter:                 Escapes.
* \|, incompatibilities with AT&T troff: Implementation Differences.
* \|, used as delimiter:                 Escapes.
* \}, and warnings:                      Warnings.
* \}, incompatibilities with AT&T troff: Implementation Differences.
* \}, used as delimiter:                 Escapes.
* \~, and translations:                  Character Translations.
* \~, difference to \<SP>:               Request and Macro Arguments.
* \~, used as delimiter:                 Escapes.
* ], as part of an identifier:           Identifiers.
* ], at end of sentence <1>:             Using Symbols.
* ], at end of sentence:                 Sentences.
* ], ending an identifier <1>:           Escapes.
* ], ending an identifier:               Identifiers.
* ], macro names starting with, and refer: Identifiers.
* aborting (ab):                         Debugging.
* absolute position operator (|):        Expressions.
* accent marks [ms]:                     ms Strings and Special Characters.
* access of postprocessor:               Postprocessor Access.
* accessing unnamed glyphs with \N:      Font File Format.
* activating kerning (kern):             Ligatures and Kerning.
* activating ligatures (lg):             Ligatures and Kerning.
* activating track kerning (tkf):        Ligatures and Kerning.
* ad request, and hyphenation margin:    Manipulating Hyphenation.
* ad request, and hyphenation space:     Manipulating Hyphenation.
* adjusting:                             Filling and Adjusting.
* adjusting and filling, manipulating:   Manipulating Filling and Adjusting.
* adjustment mode register (.j):         Manipulating Filling and Adjusting.
* adobe glyph list (AGL):                Using Symbols.
* AGL (adobe glyph list):                Using Symbols.
* alias, diversion, creating (als):      Strings.
* alias, macro, creating (als):          Strings.
* alias, number register, creating (aln): Setting Registers.
* alias, string, creating (als):         Strings.
* als request, and \$0:                  Parameters.
* am, am1, ami requests, and warnings:   Warnings.
* annotations:                           Footnotes and Annotations.
* appending to a diversion (da):         Diversions.
* appending to a file (opena):           I/O.
* appending to a macro (am):             Writing Macros.
* appending to a string (as):            Strings.
* arc, drawing (\D'a ...'):              Drawing Requests.
* argument delimiting characters:        Escapes.
* arguments to requests and macros:      Request and Macro Arguments.
* arguments, macro (\$):                 Parameters.
* arguments, of strings:                 Strings.
* arithmetic operators:                  Expressions.
* artificial fonts:                      Artificial Fonts.
* as, as1 requests, and comments:        Comments.
* as, as1 requests, and warnings:        Warnings.
* ASCII approximation output register (.A) <1>: Built-in Registers.
* ASCII approximation output register (.A): Groff Options.
* ASCII, output encoding:                Groff Options.
* asciify request, and writem:           I/O.
* assigning formats (af):                Assigning Formats.
* assignments, indirect:                 Interpolating Registers.
* assignments, nested:                   Interpolating Registers.
* AT&T troff, ms macro package differences: Differences from AT&T ms.
* auto-increment:                        Auto-increment.
* available glyphs, list (`groff_char(7)' man page): Using Symbols.
* backslash, printing (\\, \e, \E, \[rs]) <1>: Implementation Differences.
* backslash, printing (\\, \e, \E, \[rs]): Escapes.
* backspace character:                   Identifiers.
* backspace character, and translations: Character Translations.
* backtrace of input stack (backtrace):  Debugging.
* baseline:                              Sizes.
* basic unit (u):                        Measurements.
* basics of macros:                      Basics.
* bd request, and font styles:           Font Families.
* bd request, and font translations:     Changing Fonts.
* bd request, incompatibilities with AT&T troff: Implementation Differences.
* begin of conditional block (\{):       if-else.
* beginning diversion (di):              Diversions.
* blank line <1>:                        Requests.
* blank line:                            Implicit Line Breaks.
* blank line (sp):                       Basics.
* blank line macro (blm) <1>:            Blank Line Traps.
* blank line macro (blm) <2>:            Requests.
* blank line macro (blm):                Implicit Line Breaks.
* blank line traps:                      Blank Line Traps.
* blank lines, disabling:                Manipulating Spacing.
* block, conditional, begin (\{):        if-else.
* block, condititional, end (\}):        if-else.
* bold face [man]:                       Man font macros.
* bold face, imitating (bd):             Artificial Fonts.
* bottom margin:                         Page Layout.
* bounding box:                          Miscellaneous.
* box rule glyph (\[br]):                Drawing Requests.
* box, boxa requests, and warnings:      Warnings.
* boxa request, and dn (dl):             Diversions.
* bp request, and top-level diversion:   Page Control.
* bp request, and traps (.pe):           Page Location Traps.
* bp request, causing implicit linebreak: Manipulating Filling and Adjusting.
* bp request, using + and -:             Expressions.
* br glyph, and cflags:                  Using Symbols.
* break <1>:                             Manipulating Filling and Adjusting.
* break:                                 Basics.
* break (br):                            Basics.
* break request, in a while loop:        while.
* break, implicit:                       Implicit Line Breaks.
* built-in registers:                    Built-in Registers.
* bulleted list, example markup [ms]:    Lists in ms.
* c unit:                                Measurements.
* calling convention of preprocessors:   Preprocessors in man pages.
* capabilities of groff:                 groff Capabilities.
* ce request, causing implicit linebreak: Manipulating Filling and Adjusting.
* ce request, difference to .ad c:       Manipulating Filling and Adjusting.
* centered text:                         Manipulating Filling and Adjusting.
* centering lines (ce) <1>:              Manipulating Filling and Adjusting.
* centering lines (ce):                  Basics.
* centimeter unit (c):                   Measurements.
* cf request, causing implicit linebreak: Manipulating Filling and Adjusting.
* changing font family (fam, \F):        Font Families.
* changing font position (\f):           Font Positions.
* changing font style (sty):             Font Families.
* changing fonts (ft, \f):               Changing Fonts.
* changing format, and read-only registers: Assigning Formats.
* changing the font height (\H):         Artificial Fonts.
* changing the font slant (\S):          Artificial Fonts.
* changing the page number character (pc): Page Layout.
* changing trap location (ch):           Page Location Traps.
* changing type sizes (ps, \s):          Changing Type Sizes.
* changing vertical line spacing (vs):   Changing Type Sizes.
* char request, and soft hyphen character: Manipulating Hyphenation.
* char request, and translations:        Character Translations.
* char request, used with \N:            Using Symbols.
* character:                             Using Symbols.
* character properties (cflags):         Using Symbols.
* character translations:                Character Translations.
* character, backspace:                  Identifiers.
* character, backspace, and translations: Character Translations.
* character, control (.):                Requests.
* character, control, changing (cc):     Character Translations.
* character, defining (char):            Using Symbols.
* character, defining fallback (fchar, fschar, schar): Using Symbols.
* character, escape, changing (ec):      Character Translations.
* character, escape, while defining glyph: Using Symbols.
* character, field delimiting (fc):      Fields.
* character, field padding (fc):         Fields.
* character, hyphenation (\%):           Manipulating Hyphenation.
* character, leader repetition (lc):     Leaders.
* character, leader, and translations:   Character Translations.
* character, leader, non-interpreted (\a): Leaders.
* character, named (\C):                 Using Symbols.
* character, newline:                    Escapes.
* character, newline, and translations:  Character Translations.
* character, no-break control ('):       Requests.
* character, no-break control, changing (c2): Character Translations.
* character, soft hyphen, setting (shc): Manipulating Hyphenation.
* character, space:                      Escapes.
* character, special:                    Character Translations.
* character, tab:                        Escapes.
* character, tab repetition (tc):        Tabs and Fields.
* character, tab, and translations:      Character Translations.
* character, tab, non-interpreted (\t):  Tabs and Fields.
* character, tabulator:                  Tab Stops.
* character, transparent <1>:            Using Symbols.
* character, transparent:                Sentences.
* character, whitespace:                 Identifiers.
* character, zero width space (\&) <1>:  Drawing Requests.
* character, zero width space (\&) <2>:  Ligatures and Kerning.
* character, zero width space (\&):      Requests.
* characters, argument delimiting:       Escapes.
* characters, end-of-sentence:           Using Symbols.
* characters, hyphenation:               Using Symbols.
* characters, input, and output glyphs, compatibility with AT&T troff: Implementation Differences.
* characters, invalid for trf request:   I/O.
* characters, invalid input:             Identifiers.
* characters, overlapping:               Using Symbols.
* characters, special:                   Special Characters.
* characters, unnamed, accessing with \N: Font File Format.
* circle, drawing (\D'c ...'):           Drawing Requests.
* circle, solid, drawing (\D'C ...'):    Drawing Requests.
* closing file (close):                  I/O.
* code, hyphenation (hcode):             Manipulating Hyphenation.
* color, default:                        Colors.
* colors:                                Colors.
* colors, fill, unnamed (\D'F...'):      Drawing Requests.
* command prefix:                        Environment.
* command-line options:                  Groff Options.
* commands, embedded:                    Embedded Commands.
* comments:                              Comments.
* comments in font files:                Font File Format.
* comments, lining up with tabs:         Comments.
* comments, with ds:                     Strings.
* common features:                       Common Features.
* common name space of macros, diversions, and strings: Strings.
* comparison operators:                  Expressions.
* compatibility mode <1>:                Implementation Differences.
* compatibility mode:                    Warnings.
* composite glyph names:                 Using Symbols.
* conditional block, begin (\{):         if-else.
* conditional block, end (\}):           if-else.
* conditional page break (ne):           Page Control.
* conditionals and loops:                Conditionals and Loops.
* consecutive hyphenated lines (hlm):    Manipulating Hyphenation.
* constant glyph space mode (cs):        Artificial Fonts.
* contents, table of <1>:                Leaders.
* contents, table of:                    Table of Contents.
* continuation, input line (\):          Line Control.
* continuation, output line (\c):        Line Control.
* continue request, in a while loop:     while.
* continuous underlining (cu):           Artificial Fonts.
* control character (.):                 Requests.
* control character, changing (cc):      Character Translations.
* control character, no-break ('):       Requests.
* control character, no-break, changing (c2): Character Translations.
* control, line:                         Line Control.
* control, page:                         Page Control.
* conventions for input:                 Input Conventions.
* copy-in mode:                          Copy-in Mode.
* copy-in mode, and macro arguments:     Parameters.
* copy-in mode, and write requests:      I/O.
* copying environment (evc):             Environments.
* correction between italic and roman glyph (\/, \,): Ligatures and Kerning.
* correction, italic (\/):               Ligatures and Kerning.
* correction, left italic (\,):          Ligatures and Kerning.
* cover page macros, [ms]:               ms Cover Page Macros.
* cp request, and glyph definitions:     Using Symbols.
* cp1047, input encoding:                Input Encodings.
* cp1047, output encoding:               Groff Options.
* creating alias, for diversion (als):   Strings.
* creating alias, for macro (als):       Strings.
* creating alias, for number register (aln): Setting Registers.
* creating alias, for string (als):      Strings.
* creating new characters (char):        Using Symbols.
* credits:                               Credits.
* cs request, and font styles:           Font Families.
* cs request, and font translations:     Changing Fonts.
* cs request, incompatibilities with AT&T troff: Implementation Differences.
* cs request, with fractional type sizes: Fractional Type Sizes.
* current directory:                     Macro Directories.
* current input file name register (.F): Built-in Registers.
* current time:                          I/O.
* current time, hours (hours):           Built-in Registers.
* current time, minutes (minutes):       Built-in Registers.
* current time, seconds (seconds):       Built-in Registers.
* da request, and dn (dl):               Diversions.
* da request, and warnings:              Warnings.
* date, day of the month register (dy):  Built-in Registers.
* date, day of the week register (dw):   Built-in Registers.
* date, month of the year register (mo): Built-in Registers.
* date, year register (year, yr):        Built-in Registers.
* day of the month register (dy):        Built-in Registers.
* day of the week register (dw):         Built-in Registers.
* de request, and while:                 while.
* de, de1, dei requests, and warnings:   Warnings.
* debugging:                             Debugging.
* default color:                         Colors.
* default indentation [man]:             Miscellaneous man macros.
* default indentation, resetting [man]:  Man usage.
* default units:                         Default Units.
* defining character (char):             Using Symbols.
* defining fallback character (fchar, fschar, schar): Using Symbols.
* defining glyph (char):                 Using Symbols.
* defining symbol (char):                Using Symbols.
* delayed text:                          Footnotes and Annotations.
* delimited arguments, incompatibilities with AT&T troff: Implementation Differences.
* delimiting character, for fields (fc): Fields.
* delimiting characters for arguments:   Escapes.
* depth, of last glyph (.cdp):           Environments.
* DESC file, format:                     DESC File Format.
* device resolution:                     DESC File Format.
* devices for output <1>:                Output Devices.
* devices for output:                    Output device intro.
* dg glyph, at end of sentence <1>:      Using Symbols.
* dg glyph, at end of sentence:          Sentences.
* di request, and warnings:              Warnings.
* differences in implementation:         Implementation Differences.
* digit width space (\0):                Page Motions.
* digits, and delimiters:                Escapes.
* dimensions, line:                      Line Layout.
* directories for fonts:                 Font Directories.
* directories for macros:                Macro Directories.
* directory, current:                    Macro Directories.
* directory, for tmac files:             Macro Directories.
* directory, home:                       Macro Directories.
* directory, platform-specific:          Macro Directories.
* directory, site-specific <1>:          Font Directories.
* directory, site-specific:              Macro Directories.
* disabling \ (eo):                      Character Translations.
* disabling hyphenation (\%):            Manipulating Hyphenation.
* discardable horizontal space:          Manipulating Filling and Adjusting.
* discarded space in traps:              Manipulating Spacing.
* displays:                              Displays.
* displays [ms]:                         ms Displays and Keeps.
* distance to next trap register (.t):   Page Location Traps.
* ditroff, the program:                  History.
* diversion name register (.z):          Diversions.
* diversion trap, setting (dt):          Diversion Traps.
* diversion traps:                       Diversion Traps.
* diversion, appending (da):             Diversions.
* diversion, beginning (di):             Diversions.
* diversion, creating alias (als):       Strings.
* diversion, ending (di):                Diversions.
* diversion, nested:                     Diversions.
* diversion, removing (rm):              Strings.
* diversion, renaming (rn):              Strings.
* diversion, stripping final newline:    Strings.
* diversion, top-level:                  Diversions.
* diversion, top-level, and \!:          Diversions.
* diversion, top-level, and \?:          Diversions.
* diversion, top-level, and bp:          Page Control.
* diversion, unformatting (asciify):     Diversions.
* diversion, vertical position in, register (.d): Diversions.
* diversions:                            Diversions.
* diversions, and traps:                 Page Location Traps.
* diversions, shared name space with macros and strings: Strings.
* dl register, and da (boxa):            Diversions.
* dn register, and da (boxa):            Diversions.
* documents, multi-file:                 Debugging.
* documents, structuring the source code: Requests.
* double quote, in a macro argument:     Request and Macro Arguments.
* double-spacing (ls) <1>:               Manipulating Spacing.
* double-spacing (ls):                   Basics.
* double-spacing (vs, pvs):              Changing Type Sizes.
* drawing a circle (\D'c ...'):          Drawing Requests.
* drawing a line (\D'l ...'):            Drawing Requests.
* drawing a polygon (\D'p ...'):         Drawing Requests.
* drawing a solid circle (\D'C ...'):    Drawing Requests.
* drawing a solid ellipse (\D'E ...'):   Drawing Requests.
* drawing a solid polygon (\D'P ...'):   Drawing Requests.
* drawing a spline (\D'~ ...'):          Drawing Requests.
* drawing an arc (\D'a ...'):            Drawing Requests.
* drawing an ellipse (\D'e ...'):        Drawing Requests.
* drawing horizontal lines (\l):         Drawing Requests.
* drawing requests:                      Drawing Requests.
* drawing vertical lines (\L):           Drawing Requests.
* ds request, and comments:              Strings.
* ds request, and double quotes:         Request and Macro Arguments.
* ds request, and leading spaces:        Strings.
* ds, ds1 requests, and comments:        Comments.
* ds, ds1 requests, and warnings:        Warnings.
* dumping number registers (pnr):        Debugging.
* dumping symbol table (pm):             Debugging.
* dumping traps (ptr):                   Debugging.
* EBCDIC encoding:                       Tab Stops.
* EBCDIC encoding of a tab:              Tabs and Fields.
* EBCDIC encoding of backspace:          Identifiers.
* EBCDIC, input encoding:                Input Encodings.
* EBCDIC, output encoding:               Groff Options.
* el request, and warnings:              Warnings.
* ellipse, drawing (\D'e ...'):          Drawing Requests.
* ellipse, solid, drawing (\D'E ...'):   Drawing Requests.
* em glyph, and cflags:                  Using Symbols.
* em unit (m):                           Measurements.
* embedded commands:                     Embedded Commands.
* embedding PostScript:                  Embedding PostScript.
* embolding of special fonts:            Artificial Fonts.
* empty line:                            Implicit Line Breaks.
* empty line (sp):                       Basics.
* empty space before a paragraph [man]:  Miscellaneous man macros.
* en unit (n):                           Measurements.
* enabling vertical position traps (vpt): Page Location Traps.
* encoding, EBCDIC:                      Tab Stops.
* encoding, input, cp1047:               Input Encodings.
* encoding, input, EBCDIC:               Input Encodings.
* encoding, input, latin-1 (ISO 8859-1): Input Encodings.
* encoding, input, latin-2 (ISO 8859-2): Input Encodings.
* encoding, input, latin-9 (latin-0, ISO 8859-15): Input Encodings.
* encoding, output, ASCII:               Groff Options.
* encoding, output, cp1047:              Groff Options.
* encoding, output, EBCDIC:              Groff Options.
* encoding, output, latin-1 (ISO 8859-1): Groff Options.
* encoding, output, utf-8:               Groff Options.
* end of conditional block (\}):         if-else.
* end-of-input macro (em):               End-of-input Traps.
* end-of-input trap, setting (em):       End-of-input Traps.
* end-of-input traps:                    End-of-input Traps.
* end-of-sentence characters:            Using Symbols.
* ending diversion (di):                 Diversions.
* environment number/name register (.ev): Environments.
* environment variables:                 Environment.
* environment, copying (evc):            Environments.
* environment, dimensions of last glyph (.w, .cht, .cdp, .csk): Environments.
* environment, previous line length (.n): Environments.
* environment, switching (ev):           Environments.
* environments:                          Environments.
* eqn, the program:                      geqn.
* equations [ms]:                        ms Insertions.
* escape character, changing (ec):       Character Translations.
* escape character, while defining glyph: Using Symbols.
* escapes:                               Escapes.
* escaping newline characters, in strings: Strings.
* ex request, use in debugging:          Debugging.
* ex request, used with nx and rd:       I/O.
* example markup, bulleted list [ms]:    Lists in ms.
* example markup, glossary-style list [ms]: Lists in ms.
* example markup, multi-page table [ms]: Example multi-page table.
* example markup, numbered list [ms]:    Lists in ms.
* example markup, title page:            ms Cover Page Macros.
* examples of invocation:                Invocation Examples.
* exiting (ex):                          Debugging.
* expansion of strings (\*):             Strings.
* explicit hyphen (\%):                  Manipulating Hyphenation.
* expression, order of evaluation:       Expressions.
* expressions:                           Expressions.
* expressions, and space characters:     Expressions.
* extra post-vertical line space (\x):   Changing Type Sizes.
* extra post-vertical line space register (.a): Manipulating Spacing.
* extra pre-vertical line space (\x):    Changing Type Sizes.
* extra spaces:                          Filling and Adjusting.
* extremum operators (>?, <?):           Expressions.
* f unit:                                Measurements.
* f unit, and colors:                    Colors.
* fallback character, defining (fchar, fschar, schar): Using Symbols.
* fallback glyph, removing definition (rchar, rfschar): Using Symbols.
* fam request, and changing fonts:       Changing Fonts.
* fam request, and font positions:       Font Positions.
* families, font:                        Font Families.
* FDL, GNU Free Documentation License:   GNU Free Documentation License.
* features, common:                      Common Features.
* fi request, causing implicit linebreak: Manipulating Filling and Adjusting.
* field delimiting character (fc):       Fields.
* field padding character (fc):          Fields.
* fields:                                Fields.
* fields, and tabs:                      Tabs and Fields.
* figures [ms]:                          ms Insertions.
* file formats:                          File formats.
* file, appending to (opena):            I/O.
* file, closing (close):                 I/O.
* file, inclusion (so):                  I/O.
* file, opening (open):                  I/O.
* file, processing next (nx):            I/O.
* file, writing to (write):              I/O.
* files, font:                           Font Files.
* files, macro, searching:               Macro Directories.
* fill colors, unnamed (\D'F...'):       Drawing Requests.
* fill mode <1>:                         Warnings.
* fill mode <2>:                         Manipulating Filling and Adjusting.
* fill mode:                             Implicit Line Breaks.
* fill mode (fi):                        Manipulating Filling and Adjusting.
* fill mode, and \c:                     Line Control.
* filling:                               Filling and Adjusting.
* filling and adjusting, manipulating:   Manipulating Filling and Adjusting.
* final newline, stripping in diversions: Strings.
* fl request, causing implicit linebreak: Manipulating Filling and Adjusting.
* floating keep:                         Displays.
* flush output (fl):                     Debugging.
* font description file, format <1>:     Font File Format.
* font description file, format:         DESC File Format.
* font directories:                      Font Directories.
* font families:                         Font Families.
* font family, changing (fam, \F):       Font Families.
* font file, format:                     Font File Format.
* font files:                            Font Files.
* font files, comments:                  Font File Format.
* font for underlining (uf):             Artificial Fonts.
* font height, changing (\H):            Artificial Fonts.
* font path:                             Font Directories.
* font position register (.f):           Font Positions.
* font position, changing (\f):          Font Positions.
* font positions:                        Font Positions.
* font selection [man]:                  Man font macros.
* font slant, changing (\S):             Artificial Fonts.
* font style, changing (sty):            Font Families.
* font styles:                           Font Families.
* font, mounting (fp):                   Font Positions.
* font, previous (ft, \f[], \fP):        Changing Fonts.
* fonts <1>:                             Changing Fonts.
* fonts:                                 Fonts and Symbols.
* fonts, artificial:                     Artificial Fonts.
* fonts, changing (ft, \f):              Changing Fonts.
* fonts, PostScript:                     Font Families.
* fonts, searching:                      Font Directories.
* fonts, special:                        Special Fonts.
* footers <1>:                           Page Location Traps.
* footers:                               Page Layout.
* footers [ms]:                          ms Headers and Footers.
* footnotes:                             Footnotes and Annotations.
* footnotes [ms]:                        ms Footnotes.
* form letters:                          I/O.
* format of font description file:       DESC File Format.
* format of font description files:      Font File Format.
* format of font files:                  Font File Format.
* format of register (\g):               Assigning Formats.
* formats, assigning (af):               Assigning Formats.
* formats, file:                         File formats.
* fp request, and font translations:     Changing Fonts.
* fp request, incompatibilities with AT&T troff: Implementation Differences.
* fractional point sizes <1>:            Implementation Differences.
* fractional point sizes:                Fractional Type Sizes.
* fractional type sizes <1>:             Implementation Differences.
* fractional type sizes:                 Fractional Type Sizes.
* french-spacing:                        Sentences.
* fspecial request, and font styles:     Font Families.
* fspecial request, and font translations: Changing Fonts.
* fspecial request, and glyph search order: Using Symbols.
* fspecial request, and imitating bold:  Artificial Fonts.
* ft request, and font translations:     Changing Fonts.
* geqn, invoking:                        Invoking geqn.
* geqn, the program:                     geqn.
* GGL (groff glyph list):                Using Symbols.
* ggrn, invoking:                        Invoking ggrn.
* ggrn, the program:                     ggrn.
* glossary-style list, example markup [ms]: Lists in ms.
* glyph:                                 Using Symbols.
* glyph for line drawing:                Drawing Requests.
* glyph names, composite:                Using Symbols.
* glyph pile (\b):                       Drawing Requests.
* glyph properties (cflags):             Using Symbols.
* glyph, box rule (\[br]):               Drawing Requests.
* glyph, constant space:                 Artificial Fonts.
* glyph, defining (char):                Using Symbols.
* glyph, for line drawing:               Drawing Requests.
* glyph, for margins (mc):               Miscellaneous.
* glyph, italic correction (\/):         Ligatures and Kerning.
* glyph, last, dimensions (.w, .cht, .cdp, .csk): Environments.
* glyph, leader repetition (lc):         Leaders.
* glyph, left italic correction (\,):    Ligatures and Kerning.
* glyph, numbered (\N) <1>:              Using Symbols.
* glyph, numbered (\N):                  Character Translations.
* glyph, removing definition (rchar, rfschar): Using Symbols.
* glyph, soft hyphen (hy):               Manipulating Hyphenation.
* glyph, tab repetition (tc):            Tabs and Fields.
* glyph, underscore (\[ru]):             Drawing Requests.
* glyphs, available, list (`groff_char(7)' man page): Using Symbols.
* glyphs, output, and input characters, compatibility with AT&T troff: Implementation Differences.
* glyphs, overstriking (\o):             Page Motions.
* glyphs, unnamed:                       Using Symbols.
* glyphs, unnamed, accessing with \N:    Font File Format.
* GNU-specific register (.g):            Built-in Registers.
* gpic, invoking:                        Invoking gpic.
* gpic, the program:                     gpic.
* grap, the program:                     grap.
* gray shading (\D'f ...'):              Drawing Requests.
* grefer, invoking:                      Invoking grefer.
* grefer, the program:                   grefer.
* grn, the program:                      ggrn.
* grodvi, invoking:                      Invoking grodvi.
* grodvi, the program:                   grodvi.
* groff - what is it?:                   What Is groff?.
* groff capabilities:                    groff Capabilities.
* groff glyph list (GGL):                Using Symbols.
* groff invocation:                      Invoking groff.
* groff, and pi request:                 I/O.
* GROFF_BIN_PATH, environment variable:  Environment.
* GROFF_COMMAND_PREFIX, environment variable: Environment.
* GROFF_FONT_PATH, environment variable <1>: Font Directories.
* GROFF_FONT_PATH, environment variable: Environment.
* GROFF_TMAC_PATH, environment variable <1>: Macro Directories.
* GROFF_TMAC_PATH, environment variable: Environment.
* GROFF_TMPDIR, environment variable:    Environment.
* GROFF_TYPESETTER, environment variable: Environment.
* grohtml, invoking:                     Invoking grohtml.
* grohtml, registers and strings:        grohtml specific registers and strings.
* grohtml, the program <1>:              grohtml.
* grohtml, the program:                  Groff Options.
* grolbp, invoking:                      Invoking grolbp.
* grolbp, the program:                   grolbp.
* grolj4, invoking:                      Invoking grolj4.
* grolj4, the program:                   grolj4.
* grops, invoking:                       Invoking grops.
* grops, the program:                    grops.
* grotty, invoking:                      Invoking grotty.
* grotty, the program:                   grotty.
* gsoelim, invoking:                     Invoking gsoelim.
* gsoelim, the program:                  gsoelim.
* gtbl, invoking:                        Invoking gtbl.
* gtbl, the program:                     gtbl.
* gtroff, identification register (.g):  Built-in Registers.
* gtroff, interactive use:               Debugging.
* gtroff, output:                        gtroff Output.
* gtroff, process ID register ($$):      Built-in Registers.
* gtroff, reference:                     gtroff Reference.
* gxditview, invoking:                   Invoking gxditview.
* gxditview, the program:                gxditview.
* hanging indentation [man]:             Man usage.
* hcode request, and glyph definitions:  Using Symbols.
* headers <1>:                           Page Location Traps.
* headers:                               Page Layout.
* headers [ms]:                          ms Headers and Footers.
* height, font, changing (\H):           Artificial Fonts.
* height, of last glyph (.cht):          Environments.
* high-water mark register (.h):         Diversions.
* history:                               History.
* home directory:                        Macro Directories.
* horizontal discardable space:          Manipulating Filling and Adjusting.
* horizontal input line position register (hp): Page Motions.
* horizontal input line position, saving (\k): Page Motions.
* horizontal line, drawing (\l):         Drawing Requests.
* horizontal motion (\h):                Page Motions.
* horizontal output line position register (.k): Page Motions.
* horizontal resolution:                 DESC File Format.
* horizontal resolution register (.H):   Built-in Registers.
* horizontal space (\h):                 Page Motions.
* horizontal space, unformatting:        Strings.
* hours, current time (hours):           Built-in Registers.
* hpf request, and hyphenation language: Manipulating Hyphenation.
* hw request, and hyphenation language:  Manipulating Hyphenation.
* hy glyph, and cflags:                  Using Symbols.
* hyphen, explicit (\%):                 Manipulating Hyphenation.
* hyphenated lines, consecutive (hlm):   Manipulating Hyphenation.
* hyphenating characters:                Using Symbols.
* hyphenation:                           Hyphenation.
* hyphenation character (\%):            Manipulating Hyphenation.
* hyphenation code (hcode):              Manipulating Hyphenation.
* hyphenation language register (.hla):  Manipulating Hyphenation.
* hyphenation margin (hym):              Manipulating Hyphenation.
* hyphenation margin register (.hym):    Manipulating Hyphenation.
* hyphenation patterns (hpf):            Manipulating Hyphenation.
* hyphenation restrictions register (.hy): Manipulating Hyphenation.
* hyphenation space (hys):               Manipulating Hyphenation.
* hyphenation space register (.hys):     Manipulating Hyphenation.
* hyphenation, disabling (\%):           Manipulating Hyphenation.
* hyphenation, manipulating:             Manipulating Hyphenation.
* i unit:                                Measurements.
* i/o:                                   I/O.
* IBM cp1047 input encoding:             Input Encodings.
* IBM cp1047 output encoding:            Groff Options.
* identifiers:                           Identifiers.
* identifiers, undefined:                Identifiers.
* ie request, and warnings:              Warnings.
* if request, and the ! operator:        Expressions.
* if request, operators to use with:     Operators in Conditionals.
* if-else:                               if-else.
* imitating bold face (bd):              Artificial Fonts.
* implementation differences:            Implementation Differences.
* implicit breaks of lines:              Implicit Line Breaks.
* implicit line breaks:                  Implicit Line Breaks.
* in request, causing implicit linebreak: Manipulating Filling and Adjusting.
* in request, using + and -:             Expressions.
* inch unit (i):                         Measurements.
* including a file (so):                 I/O.
* incompatibilities with AT&T troff:     Implementation Differences.
* increment value without changing the register: Auto-increment.
* increment, automatic:                  Auto-increment.
* indentaion, resetting to default [man]: Man usage.
* indentation (in):                      Line Layout.
* index, in macro package:               Indices.
* indirect assignments:                  Interpolating Registers.
* input and output requests:             I/O.
* input characters and output glyphs, compatibility with AT&T troff: Implementation Differences.
* input characters, invalid:             Identifiers.
* input conventions:                     Input Conventions.
* input encoding, cp1047:                Input Encodings.
* input encoding, EBCDIC:                Input Encodings.
* input encoding, latin-1 (ISO 8859-1):  Input Encodings.
* input encoding, latin-2 (ISO 8859-2):  Input Encodings.
* input encoding, latin-9 (latin-9, ISO 8859-15): Input Encodings.
* input file name, current, register (.F): Built-in Registers.
* input level in delimited arguments:    Implementation Differences.
* input line continuation (\):           Line Control.
* input line number register (.c, c.):   Built-in Registers.
* input line number, setting (lf):       Debugging.
* input line position, horizontal, saving (\k): Page Motions.
* input line trap, setting (it):         Input Line Traps.
* input line traps:                      Input Line Traps.
* input line traps and interrupted lines (itc): Input Line Traps.
* input line, horizontal position, register (hp): Page Motions.
* input stack, backtrace (backtrace):    Debugging.
* input stack, setting limit:            Debugging.
* input token:                           Gtroff Internals.
* input, 8-bit:                          Font File Format.
* input, standard, reading from (rd):    I/O.
* inserting horizontal space (\h):       Page Motions.
* installation:                          Installation.
* interactive use of gtroff:             Debugging.
* intermediate output:                   gtroff Output.
* interpolating registers (\n):          Interpolating Registers.
* interpolation of strings (\*):         Strings.
* interrupted line:                      Line Control.
* interrupted line register (.int):      Line Control.
* interrupted lines and input line traps (itc): Input Line Traps.
* introduction:                          Introduction.
* invalid characters for trf request:    I/O.
* invalid input characters:              Identifiers.
* invocation examples:                   Invocation Examples.
* invoking geqn:                         Invoking geqn.
* invoking ggrn:                         Invoking ggrn.
* invoking gpic:                         Invoking gpic.
* invoking grefer:                       Invoking grefer.
* invoking grodvi:                       Invoking grodvi.
* invoking groff:                        Invoking groff.
* invoking grohtml:                      Invoking grohtml.
* invoking grolbp:                       Invoking grolbp.
* invoking grolj4:                       Invoking grolj4.
* invoking grops:                        Invoking grops.
* invoking grotty:                       Invoking grotty.
* invoking gsoelim:                      Invoking gsoelim.
* invoking gtbl:                         Invoking gtbl.
* invoking gxditview:                    Invoking gxditview.
* ISO 8859-1 (latin-1), input encoding:  Input Encodings.
* ISO 8859-1 (latin-1), output encoding: Groff Options.
* ISO 8859-15 (latin-9, latin-0), input encoding: Input Encodings.
* ISO 8859-2 (latin-2), input encoding:  Input Encodings.
* italic correction (\/):                Ligatures and Kerning.
* italic fonts [man]:                    Man font macros.
* italic glyph, correction after roman glyph (\,): Ligatures and Kerning.
* italic glyph, correction before roman glyph (\/): Ligatures and Kerning.
* justifying text:                       Manipulating Filling and Adjusting.
* justifying text (rj):                  Manipulating Filling and Adjusting.
* keep:                                  Displays.
* keep, floating:                        Displays.
* keeps [ms]:                            ms Displays and Keeps.
* kerning and ligatures:                 Ligatures and Kerning.
* kerning enabled register (.kern):      Ligatures and Kerning.
* kerning, activating (kern):            Ligatures and Kerning.
* kerning, track:                        Ligatures and Kerning.
* landscape page orientation:            Paper Size.
* last glyph, dimensions (.w, .cht, .cdp, .csk): Environments.
* last-requested point size registers (.psr, .sr): Fractional Type Sizes.
* latin-1 (ISO 8859-1), input encoding:  Input Encodings.
* latin-1 (ISO 8859-1), output encoding: Groff Options.
* latin-2 (ISO 8859-2), input encoding:  Input Encodings.
* latin-9 (latin-0, ISO 8859-15), input encoding: Input Encodings.
* layout, line:                          Line Layout.
* layout, page:                          Page Layout.
* lc request, and glyph definitions:     Using Symbols.
* leader character:                      Leaders.
* leader character, and translations:    Character Translations.
* leader character, non-interpreted (\a): Leaders.
* leader repetition character (lc):      Leaders.
* leaders:                               Leaders.
* leading:                               Sizes.
* leading spaces:                        Filling and Adjusting.
* leading spaces with ds:                Strings.
* left italic correction (\,):           Ligatures and Kerning.
* left margin (po):                      Line Layout.
* left margin, how to move [man]:        Man usage.
* length of a string (length):           Strings.
* length of line (ll):                   Line Layout.
* length of page (pl):                   Page Layout.
* length of previous line (.n):          Environments.
* length of title line (lt):             Page Layout.
* letters, form:                         I/O.
* level of warnings (warn):              Debugging.
* ligature:                              Using Symbols.
* ligatures and kerning:                 Ligatures and Kerning.
* ligatures enabled register (.lg):      Ligatures and Kerning.
* ligatures, activating (lg):            Ligatures and Kerning.
* limitations of \b escape:              Drawing Requests.
* line break <1>:                        Manipulating Filling and Adjusting.
* line break <2>:                        Implicit Line Breaks.
* line break:                            Basics.
* line break (br):                       Basics.
* line breaks, with vertical space [man]: Man usage.
* line breaks, without vertical space [man]: Man usage.
* line control:                          Line Control.
* line dimensions:                       Line Layout.
* line drawing glyph:                    Drawing Requests.
* line indentation (in):                 Line Layout.
* line layout:                           Line Layout.
* line length (ll):                      Line Layout.
* line length register (.l):             Line Layout.
* line length, previous (.n):            Environments.
* line number, input, register (.c, c.): Built-in Registers.
* line number, output, register (ln):    Built-in Registers.
* line numbers, printing (nm):           Miscellaneous.
* line space, extra post-vertical (\x):  Changing Type Sizes.
* line space, extra pre-vertical (\x):   Changing Type Sizes.
* line spacing register (.L):            Manipulating Spacing.
* line spacing, post-vertical (pvs):     Changing Type Sizes.
* line thickness (\D't ...'):            Drawing Requests.
* line, blank:                           Implicit Line Breaks.
* line, drawing (\D'l ...'):             Drawing Requests.
* line, empty (sp):                      Basics.
* line, horizontal, drawing (\l):        Drawing Requests.
* line, implicit breaks:                 Implicit Line Breaks.
* line, input, continuation (\):         Line Control.
* line, input, horizontal position, register (hp): Page Motions.
* line, input, horizontal position, saving (\k): Page Motions.
* line, interrupted:                     Line Control.
* line, output, continuation (\c):       Line Control.
* line, output, horizontal position, register (.k): Page Motions.
* line, vertical, drawing (\L):          Drawing Requests.
* line-tabs mode:                        Tabs and Fields.
* lines, blank, disabling:               Manipulating Spacing.
* lines, centering (ce) <1>:             Manipulating Filling and Adjusting.
* lines, centering (ce):                 Basics.
* lines, consecutive hyphenated (hlm):   Manipulating Hyphenation.
* lines, interrupted, and input line traps (itc): Input Line Traps.
* list:                                  Displays.
* list of available glyphs (`groff_char(7)' man page): Using Symbols.
* ll request, using + and -:             Expressions.
* location, vertical, page, marking (mk): Page Motions.
* location, vertical, page, returning to marked (rt): Page Motions.
* logical operators:                     Expressions.
* long names:                            Implementation Differences.
* loops and conditionals:                Conditionals and Loops.
* lq glyph, and lq string [man]:         Predefined man strings.
* ls request, alternative to (pvs):      Changing Type Sizes.
* lt request, using + and -:             Expressions.
* M unit:                                Measurements.
* m unit:                                Measurements.
* machine unit (u):                      Measurements.
* macro arguments:                       Request and Macro Arguments.
* macro basics:                          Basics.
* macro directories:                     Macro Directories.
* macro files, searching:                Macro Directories.
* macro name register (\$0):             Parameters.
* macro names, starting with [ or ], and refer: Identifiers.
* macro packages <1>:                    Macro Packages.
* macro packages:                        Macro Package Intro.
* macro packages, structuring the source code: Requests.
* macro, appending (am):                 Writing Macros.
* macro, arguments (\$):                 Parameters.
* macro, creating alias (als):           Strings.
* macro, end-of-input (em):              End-of-input Traps.
* macro, removing (rm):                  Strings.
* macro, renaming (rn):                  Strings.
* macros:                                Macros.
* macros for manual pages [man]:         Man usage.
* macros, recursive:                     while.
* macros, searching:                     Macro Directories.
* macros, shared name space with strings and diversions: Strings.
* macros, tutorial for users:            Tutorial for Macro Users.
* macros, writing:                       Writing Macros.
* major quotes:                          Displays.
* major version number register (.x):    Built-in Registers.
* man macros:                            Man usage.
* man macros, bold face:                 Man font macros.
* man macros, custom headers and footers: Optional man extensions.
* man macros, default indentation:       Miscellaneous man macros.
* man macros, empty space before a paragraph: Miscellaneous man macros.
* man macros, hanging indentation:       Man usage.
* man macros, how to set fonts:          Man font macros.
* man macros, italic fonts:              Man font macros.
* man macros, line breaks with vertical space: Man usage.
* man macros, line breaks without vertical space: Man usage.
* man macros, moving left margin:        Man usage.
* man macros, resetting default indentation: Man usage.
* man macros, tab stops:                 Miscellaneous man macros.
* man macros, Ultrix-specific:           Optional man extensions.
* man pages:                             man.
* manipulating filling and adjusting:    Manipulating Filling and Adjusting.
* manipulating hyphenation:              Manipulating Hyphenation.
* manipulating spacing:                  Manipulating Spacing.
* manmacros, BSD compatibility:          Miscellaneous man macros.
* manual pages:                          man.
* margin for hyphenation (hym):          Manipulating Hyphenation.
* margin glyph (mc):                     Miscellaneous.
* margin, bottom:                        Page Layout.
* margin, left (po):                     Line Layout.
* margin, top:                           Page Layout.
* mark, high-water, register (.h):       Diversions.
* marking vertical page location (mk):   Page Motions.
* maximum values of Roman numerals:      Assigning Formats.
* mdoc macros:                           mdoc.
* me macro package:                      me.
* measurement unit:                      Measurements.
* measurements:                          Measurements.
* measurements, specifying safely:       Default Units.
* minimum values of Roman numerals:      Assigning Formats.
* minor version number register (.y):    Built-in Registers.
* minutes, current time (minutes):       Built-in Registers.
* mm macro package:                      mm.
* mode for constant glyph space (cs):    Artificial Fonts.
* mode, compatibility:                   Implementation Differences.
* mode, copy-in:                         Copy-in Mode.
* mode, copy-in, and write requests:     I/O.
* mode, fill <1>:                        Warnings.
* mode, fill <2>:                        Manipulating Filling and Adjusting.
* mode, fill:                            Implicit Line Breaks.
* mode, fill (fi):                       Manipulating Filling and Adjusting.
* mode, fill, and \c:                    Line Control.
* mode, line-tabs:                       Tabs and Fields.
* mode, no-fill (nf):                    Manipulating Filling and Adjusting.
* mode, no-fill, and \c:                 Line Control.
* mode, no-space (ns):                   Manipulating Spacing.
* mode, nroff:                           Troff and Nroff Mode.
* mode, safer <1>:                       I/O.
* mode, safer <2>:                       Macro Directories.
* mode, safer:                           Groff Options.
* mode, troff:                           Troff and Nroff Mode.
* mode, unsafe <1>:                      I/O.
* mode, unsafe <2>:                      Macro Directories.
* mode, unsafe:                          Groff Options.
* month of the year register (mo):       Built-in Registers.
* motion operators:                      Expressions.
* motion, horizontal (\h):               Page Motions.
* motion, vertical (\v):                 Page Motions.
* motions, page:                         Page Motions.
* mounting font (fp):                    Font Positions.
* ms macros:                             ms.
* ms macros, accent marks:               ms Strings and Special Characters.
* ms macros, body text:                  ms Body Text.
* ms macros, cover page:                 ms Cover Page Macros.
* ms macros, creating table of contents: ms TOC.
* ms macros, differences from AT&T:      Differences from AT&T ms.
* ms macros, displays:                   ms Displays and Keeps.
* ms macros, document control registers: ms Document Control Registers.
* ms macros, equations:                  ms Insertions.
* ms macros, figures:                    ms Insertions.
* ms macros, footers:                    ms Headers and Footers.
* ms macros, footnotes:                  ms Footnotes.
* ms macros, general structure:          General ms Structure.
* ms macros, headers:                    ms Headers and Footers.
* ms macros, headings:                   Headings in ms.
* ms macros, highlighting:               Highlighting in ms.
* ms macros, keeps:                      ms Displays and Keeps.
* ms macros, lists:                      Lists in ms.
* ms macros, margins:                    ms Margins.
* ms macros, multiple columns:           ms Multiple Columns.
* ms macros, nested lists:               Lists in ms.
* ms macros, page layout:                ms Page Layout.
* ms macros, paragraph handling:         Paragraphs in ms.
* ms macros, references:                 ms Insertions.
* ms macros, special characters:         ms Strings and Special Characters.
* ms macros, strings:                    ms Strings and Special Characters.
* ms macros, tables:                     ms Insertions.
* multi-file documents:                  Debugging.
* multi-line strings:                    Strings.
* multi-page table, example markup [ms]: Example multi-page table.
* multiple columns [ms]:                 ms Multiple Columns.
* n unit:                                Measurements.
* name space, common, of macros, diversions, and strings: Strings.
* named character (\C):                  Using Symbols.
* names, long:                           Implementation Differences.
* ne request, and the .trunc register:   Page Location Traps.
* ne request, comparison with sv:        Page Control.
* negating register values:              Setting Registers.
* nested assignments:                    Interpolating Registers.
* nested diversions:                     Diversions.
* nested lists [ms]:                     Lists in ms.
* new page (bp) <1>:                     Page Control.
* new page (bp):                         Basics.
* newline character <1>:                 Escapes.
* newline character:                     Identifiers.
* newline character, and translations:   Character Translations.
* newline character, in strings, escaping: Strings.
* newline, final, stripping in diversions: Strings.
* next file, processing (nx):            I/O.
* next free font position register (.fp): Font Positions.
* nf request, causing implicit linebreak: Manipulating Filling and Adjusting.
* nl register, and .d:                   Diversions.
* nl register, difference to .h:         Diversions.
* nm request, using + and -:             Expressions.
* no-break control character ('):        Requests.
* no-break control character, changing (c2): Character Translations.
* no-fill mode (nf):                     Manipulating Filling and Adjusting.
* no-fill mode, and \c:                  Line Control.
* no-space mode (ns):                    Manipulating Spacing.
* node, output:                          Gtroff Internals.
* nr request, and warnings:              Warnings.
* nr request, using + and -:             Expressions.
* nroff mode:                            Troff and Nroff Mode.
* nroff, the program:                    History.
* number of arguments register (.$):     Parameters.
* number register, creating alias (aln): Setting Registers.
* number register, removing (rr):        Setting Registers.
* number register, renaming (rnn):       Setting Registers.
* number registers, dumping (pnr):       Debugging.
* number, input line, setting (lf):      Debugging.
* number, page (pn):                     Page Layout.
* numbered glyph (\N) <1>:               Using Symbols.
* numbered glyph (\N):                   Character Translations.
* numbered list, example markup [ms]:    Lists in ms.
* numbers, and delimiters:               Escapes.
* numbers, line, printing (nm):          Miscellaneous.
* numerals, Roman:                       Assigning Formats.
* numeric expression, valid:             Expressions.
* offset, page (po):                     Line Layout.
* open request, and safer mode:          Groff Options.
* opena request, and safer mode:         Groff Options.
* opening file (open):                   I/O.
* operator, scaling:                     Expressions.
* operators, arithmetic:                 Expressions.
* operators, as delimiters:              Escapes.
* operators, comparison:                 Expressions.
* operators, extremum (>?, <?):          Expressions.
* operators, logical:                    Expressions.
* operators, motion:                     Expressions.
* operators, unary:                      Expressions.
* options:                               Groff Options.
* order of evaluation in expressions:    Expressions.
* orientation, landscape:                Paper Size.
* orphan lines, preventing with ne:      Page Control.
* os request, and no-space mode:         Page Control.
* output and input requests:             I/O.
* output device name string register (.T) <1>: Built-in Registers.
* output device name string register (.T): Groff Options.
* output device usage number register (.T): Groff Options.
* output devices <1>:                    Output Devices.
* output devices:                        Output device intro.
* output encoding, ASCII:                Groff Options.
* output encoding, cp1047:               Groff Options.
* output encoding, EBCDIC:               Groff Options.
* output encoding, latin-1 (ISO 8859-1): Groff Options.
* output encoding, utf-8:                Groff Options.
* output glyphs, and input characters,compatibility with AT&T troff: Implementation Differences.
* output line number register (ln):      Built-in Registers.
* output line, continuation (\c):        Line Control.
* output line, horizontal position, register (.k): Page Motions.
* output node:                           Gtroff Internals.
* output request, and \!:                Diversions.
* output, flush (fl):                    Debugging.
* output, gtroff:                        gtroff Output.
* output, intermediate:                  gtroff Output.
* output, suppressing (\O):              Suppressing output.
* output, transparent (\!, \?):          Diversions.
* output, transparent (cf, trf):         I/O.
* output, transparent, incompatibilities with AT&T troff: Implementation Differences.
* output, troff:                         gtroff Output.
* overlapping characters:                Using Symbols.
* overstriking glyphs (\o):              Page Motions.
* P unit:                                Measurements.
* p unit:                                Measurements.
* packages, macros:                      Macro Packages.
* padding character, for fields (fc):    Fields.
* page break, conditional (ne):          Page Control.
* page control:                          Page Control.
* page ejecting register (.pe):          Page Location Traps.
* page footers:                          Page Location Traps.
* page headers:                          Page Location Traps.
* page layout:                           Page Layout.
* page layout [ms]:                      ms Page Layout.
* page length (pl):                      Page Layout.
* page length register (.p):             Page Layout.
* page location traps:                   Page Location Traps.
* page location, vertical, marking (mk): Page Motions.
* page location, vertical, returning to marked (rt): Page Motions.
* page motions:                          Page Motions.
* page number (pn):                      Page Layout.
* page number character (%):             Page Layout.
* page number character, changing (pc):  Page Layout.
* page number register (%):              Page Layout.
* page offset (po):                      Line Layout.
* page orientation, landscape:           Paper Size.
* page, new (bp):                        Page Control.
* paper formats:                         Paper Formats.
* paper size:                            Paper Size.
* paragraphs:                            Paragraphs.
* parameters:                            Parameters.
* parentheses:                           Expressions.
* path, for font files:                  Font Directories.
* path, for tmac files:                  Macro Directories.
* patterns for hyphenation (hpf):        Manipulating Hyphenation.
* pi request, and groff:                 I/O.
* pi request, and safer mode:            Groff Options.
* pic, the program:                      gpic.
* pica unit (P):                         Measurements.
* pile, glyph (\b):                      Drawing Requests.
* pl request, using + and -:             Expressions.
* planting a trap:                       Traps.
* platform-specific directory:           Macro Directories.
* pn request, using + and -:             Expressions.
* po request, using + and -:             Expressions.
* point size registers (.s, .ps):        Changing Type Sizes.
* point size registers, last-requested (.psr, .sr): Fractional Type Sizes.
* point sizes, changing (ps, \s):        Changing Type Sizes.
* point sizes, fractional <1>:           Implementation Differences.
* point sizes, fractional:               Fractional Type Sizes.
* point unit (p):                        Measurements.
* polygon, drawing (\D'p ...'):          Drawing Requests.
* polygon, solid, drawing (\D'P ...'):   Drawing Requests.
* position of lowest text line (.h):     Diversions.
* position, absolute, operator (|):      Expressions.
* position, horizontal input line, saving (\k): Page Motions.
* position, horizontal, in input line, register (hp): Page Motions.
* position, horizontal, in output line, register (.k): Page Motions.
* position, vertical, in diversion, register (.d): Diversions.
* positions, font:                       Font Positions.
* post-vertical line spacing:            Changing Type Sizes.
* post-vertical line spacing register (.pvs): Changing Type Sizes.
* post-vertical line spacing, changing (pvs): Changing Type Sizes.
* postprocessor access:                  Postprocessor Access.
* postprocessors:                        Output device intro.
* PostScript fonts:                      Font Families.
* PostScript, bounding box:              Miscellaneous.
* PostScript, embedding:                 Embedding PostScript.
* prefix, for commands:                  Environment.
* preprocessor, calling convention:      Preprocessors in man pages.
* preprocessors <1>:                     Preprocessors.
* preprocessors:                         Preprocessor Intro.
* previous font (ft, \f[], \fP):         Changing Fonts.
* previous line length (.n):             Environments.
* print current page register (.P):      Groff Options.
* printing backslash (\\, \e, \E, \[rs]) <1>: Implementation Differences.
* printing backslash (\\, \e, \E, \[rs]): Escapes.
* printing line numbers (nm):            Miscellaneous.
* printing to stderr (tm, tm1, tmc):     Debugging.
* printing, zero-width (\z, \Z):         Page Motions.
* process ID of gtroff register ($$):    Built-in Registers.
* processing next file (nx):             I/O.
* properties of characters (cflags):     Using Symbols.
* properties of glyphs (cflags):         Using Symbols.
* ps request, and constant glyph space mode: Artificial Fonts.
* ps request, incompatibilities with AT&T troff: Implementation Differences.
* ps request, using + and -:             Expressions.
* ps request, with fractional type sizes: Fractional Type Sizes.
* pso request, and safer mode:           Groff Options.
* pvs request, using + and -:            Expressions.
* quotes, major:                         Displays.
* quotes, trailing:                      Strings.
* radicalex glyph, and cflags:           Using Symbols.
* ragged-left:                           Manipulating Filling and Adjusting.
* ragged-right:                          Manipulating Filling and Adjusting.
* rc request, and glyph definitions:     Using Symbols.
* read-only register, changing format:   Assigning Formats.
* reading from standard input (rd):      I/O.
* recursive macros:                      while.
* refer, and macro names starting with [ or ]: Identifiers.
* refer, the program:                    grefer.
* reference, gtroff:                     gtroff Reference.
* references [ms]:                       ms Insertions.
* register, creating alias (aln):        Setting Registers.
* register, format (\g):                 Assigning Formats.
* register, removing (rr):               Setting Registers.
* register, renaming (rnn):              Setting Registers.
* registers:                             Registers.
* registers specific to grohtml:         grohtml specific registers and strings.
* registers, built-in:                   Built-in Registers.
* registers, interpolating (\n):         Interpolating Registers.
* registers, setting (nr, \R):           Setting Registers.
* removing diversion (rm):               Strings.
* removing glyph definition (rchar, rfschar): Using Symbols.
* removing macro (rm):                   Strings.
* removing number register (rr):         Setting Registers.
* removing request (rm):                 Strings.
* removing string (rm):                  Strings.
* renaming diversion (rn):               Strings.
* renaming macro (rn):                   Strings.
* renaming number register (rnn):        Setting Registers.
* renaming request (rn):                 Strings.
* renaming string (rn):                  Strings.
* request arguments:                     Request and Macro Arguments.
* request, removing (rm):                Strings.
* request, renaming (rn):                Strings.
* request, undefined:                    Comments.
* requests:                              Requests.
* requests for drawing:                  Drawing Requests.
* requests for input and output:         I/O.
* resolution, device:                    DESC File Format.
* resolution, horizontal:                DESC File Format.
* resolution, horizontal, register (.H): Built-in Registers.
* resolution, vertical:                  DESC File Format.
* resolution, vertical, register (.V):   Built-in Registers.
* returning to marked vertical page location (rt): Page Motions.
* revision number register (.Y):         Built-in Registers.
* rf, the program:                       History.
* right-justifying (rj):                 Manipulating Filling and Adjusting.
* rj request, causing implicit linebreak: Manipulating Filling and Adjusting.
* rn glyph, and cflags:                  Using Symbols.
* roff, the program:                     History.
* roman glyph, correction after italic glyph (\/): Ligatures and Kerning.
* roman glyph, correction before italic glyph (\,): Ligatures and Kerning.
* Roman numerals:                        Assigning Formats.
* Roman numerals, maximum and minimum:   Assigning Formats.
* rq glyph, and rq string [man]:         Predefined man strings.
* rq glyph, at end of sentence <1>:      Using Symbols.
* rq glyph, at end of sentence:          Sentences.
* rt request, using + and -:             Expressions.
* ru glyph, and cflags:                  Using Symbols.
* runoff, the program:                   History.
* s unit <1>:                            Fractional Type Sizes.
* s unit:                                Measurements.
* safer mode <1>:                        I/O.
* safer mode <2>:                        Macro Directories.
* safer mode:                            Groff Options.
* saving horizontal input line position (\k): Page Motions.
* scaling operator:                      Expressions.
* searching fonts:                       Font Directories.
* searching macro files:                 Macro Directories.
* searching macros:                      Macro Directories.
* seconds, current time (seconds):       Built-in Registers.
* sentence space:                        Sentences.
* sentence space size register (.sss):   Manipulating Filling and Adjusting.
* sentences:                             Sentences.
* setting diversion trap (dt):           Diversion Traps.
* setting end-of-input trap (em):        End-of-input Traps.
* setting input line number (lf):        Debugging.
* setting input line trap (it):          Input Line Traps.
* setting registers (nr, \R):            Setting Registers.
* shading filled objects (\D'f ...'):    Drawing Requests.
* shc request, and translations:         Character Translations.
* site-specific directory <1>:           Font Directories.
* site-specific directory:               Macro Directories.
* size of sentence space register (.sss): Manipulating Filling and Adjusting.
* size of type:                          Sizes.
* size of word space register (.ss):     Manipulating Filling and Adjusting.
* size, paper:                           Paper Size.
* sizes:                                 Sizes.
* sizes, fractional <1>:                 Implementation Differences.
* sizes, fractional:                     Fractional Type Sizes.
* skew, of last glyph (.csk):            Environments.
* slant, font, changing (\S):            Artificial Fonts.
* soelim, the program:                   gsoelim.
* soft hyphen character, setting (shc):  Manipulating Hyphenation.
* soft hyphen glyph (hy):                Manipulating Hyphenation.
* solid circle, drawing (\D'C ...'):     Drawing Requests.
* solid ellipse, drawing (\D'E ...'):    Drawing Requests.
* solid polygon, drawing (\D'P ...'):    Drawing Requests.
* sp request, and no-space mode:         Manipulating Spacing.
* sp request, and traps:                 Manipulating Spacing.
* sp request, causing implicit linebreak: Manipulating Filling and Adjusting.
* space between sentences:               Sentences.
* space between sentences register (.sss): Manipulating Filling and Adjusting.
* space between words register (.ss):    Manipulating Filling and Adjusting.
* space character:                       Escapes.
* space character, zero width (\&) <1>:  Drawing Requests.
* space character, zero width (\&) <2>:  Ligatures and Kerning.
* space character, zero width (\&):      Requests.
* space characters, in expressions:      Expressions.
* space, discardable, horizontal:        Manipulating Filling and Adjusting.
* space, discarded, in traps:            Manipulating Spacing.
* space, horizontal (\h):                Page Motions.
* space, horizontal, unformatting:       Strings.
* space, unbreakable:                    Page Motions.
* space, vertical, unit (v):             Measurements.
* space, width of a digit (\0):          Page Motions.
* spaces with ds:                        Strings.
* spaces, in a macro argument:           Request and Macro Arguments.
* spaces, leading and trailing:          Filling and Adjusting.
* spacing:                               Basics.
* spacing, manipulating:                 Manipulating Spacing.
* spacing, vertical:                     Sizes.
* special characters <1>:                Special Characters.
* special characters:                    Character Translations.
* special characters [ms]:               ms Strings and Special Characters.
* special fonts <1>:                     Font File Format.
* special fonts <2>:                     Special Fonts.
* special fonts:                         Using Symbols.
* special fonts, emboldening:            Artificial Fonts.
* special request, and font translations: Changing Fonts.
* special request, and glyph search order: Using Symbols.
* spline, drawing (\D'~ ...'):           Drawing Requests.
* springing a trap:                      Traps.
* sqrtex glyph, and cflags:              Using Symbols.
* stacking glyphs (\b):                  Drawing Requests.
* standard input, reading from (rd):     I/O.
* stderr, printing to (tm, tm1, tmc):    Debugging.
* stops, tabulator:                      Tab Stops.
* string arguments:                      Strings.
* string expansion (\*):                 Strings.
* string interpolation (\*):             Strings.
* string, appending (as):                Strings.
* string, creating alias (als):          Strings.
* string, length of (length):            Strings.
* string, removing (rm):                 Strings.
* string, renaming (rn):                 Strings.
* strings:                               Strings.
* strings [ms]:                          ms Strings and Special Characters.
* strings specific to grohtml:           grohtml specific registers and strings.
* strings, multi-line:                   Strings.
* strings, shared name space with macros and diversions: Strings.
* stripping final newline in diversions: Strings.
* structuring source code of documents or macro packages: Requests.
* sty request, and changing fonts:       Changing Fonts.
* sty request, and font positions:       Font Positions.
* sty request, and font translations:    Changing Fonts.
* styles, font:                          Font Families.
* substring (substring):                 Strings.
* suppressing output (\O):               Suppressing output.
* sv request, and no-space mode:         Page Control.
* switching environments (ev):           Environments.
* sy request, and safer mode:            Groff Options.
* symbol:                                Using Symbols.
* symbol table, dumping (pm):            Debugging.
* symbol, defining (char):               Using Symbols.
* symbols, using:                        Using Symbols.
* system() return value register (systat): I/O.
* tab character <1>:                     Escapes.
* tab character:                         Tab Stops.
* tab character, and translations:       Character Translations.
* tab character, non-interpreted (\t):   Tabs and Fields.
* tab repetition character (tc):         Tabs and Fields.
* tab settings register (.tabs):         Tabs and Fields.
* tab stops:                             Tab Stops.
* tab stops [man]:                       Miscellaneous man macros.
* tab stops, for TTY output devices:     Tabs and Fields.
* tab, line-tabs mode:                   Tabs and Fields.
* table of contents <1>:                 Leaders.
* table of contents:                     Table of Contents.
* table of contents, creating [ms]:      ms TOC.
* tables [ms]:                           ms Insertions.
* tabs, and fields:                      Tabs and Fields.
* tabs, before comments:                 Comments.
* tbl, the program:                      gtbl.
* text line, position of lowest (.h):    Diversions.
* text, gtroff processing:               Text.
* text, justifying:                      Manipulating Filling and Adjusting.
* text, justifying (rj):                 Manipulating Filling and Adjusting.
* thickness of lines (\D't ...'):        Drawing Requests.
* three-part title (tl):                 Page Layout.
* ti request, causing implicit linebreak: Manipulating Filling and Adjusting.
* ti request, using + and -:             Expressions.
* time, current:                         I/O.
* time, current, hours (hours):          Built-in Registers.
* time, current, minutes (minutes):      Built-in Registers.
* time, current, seconds (seconds):      Built-in Registers.
* title line (tl):                       Page Layout.
* title line length register (.lt):      Page Layout.
* title line, length (lt):               Page Layout.
* title page, example markup:            ms Cover Page Macros.
* titles:                                Page Layout.
* tkf request, and font styles:          Font Families.
* tkf request, and font translations:    Changing Fonts.
* tkf request, with fractional type sizes: Fractional Type Sizes.
* tl request, and mc:                    Miscellaneous.
* tmac, directory:                       Macro Directories.
* tmac, path:                            Macro Directories.
* TMPDIR, environment variable:          Environment.
* token, input:                          Gtroff Internals.
* top margin:                            Page Layout.
* top-level diversion:                   Diversions.
* top-level diversion, and \!:           Diversions.
* top-level diversion, and \?:           Diversions.
* top-level diversion, and bp:           Page Control.
* tr request, and glyph definitions:     Using Symbols.
* tr request, and soft hyphen character: Manipulating Hyphenation.
* tr request, incompatibilities with AT&T troff: Implementation Differences.
* track kerning:                         Ligatures and Kerning.
* track kerning, activating (tkf):       Ligatures and Kerning.
* trailing quotes:                       Strings.
* trailing spaces:                       Filling and Adjusting.
* translations of characters:            Character Translations.
* transparent characters <1>:            Using Symbols.
* transparent characters:                Sentences.
* transparent output (\!, \?):           Diversions.
* transparent output (cf, trf):          I/O.
* transparent output, incompatibilities with AT&T troff: Implementation Differences.
* trap, changing location (ch):          Page Location Traps.
* trap, distance, register (.t):         Page Location Traps.
* trap, diversion, setting (dt):         Diversion Traps.
* trap, end-of-input, setting (em):      End-of-input Traps.
* trap, input line, setting (it):        Input Line Traps.
* trap, planting:                        Traps.
* trap, springing:                       Traps.
* traps:                                 Traps.
* traps, and discarded space:            Manipulating Spacing.
* traps, and diversions:                 Page Location Traps.
* traps, blank line:                     Blank Line Traps.
* traps, diversion:                      Diversion Traps.
* traps, dumping (ptr):                  Debugging.
* traps, end-of-input:                   End-of-input Traps.
* traps, input line:                     Input Line Traps.
* traps, input line, and interrupted lines (itc): Input Line Traps.
* traps, page location:                  Page Location Traps.
* traps, sprung by bp request (.pe):     Page Location Traps.
* trf request, and invalid characters:   I/O.
* trf request, causing implicit linebreak: Manipulating Filling and Adjusting.
* trin request, and asciify:             Diversions.
* troff mode:                            Troff and Nroff Mode.
* troff output:                          gtroff Output.
* truncated vertical space register (.trunc): Page Location Traps.
* tutorial for macro users:              Tutorial for Macro Users.
* type size:                             Sizes.
* type size registers (.s, .ps):         Changing Type Sizes.
* type sizes, changing (ps, \s):         Changing Type Sizes.
* type sizes, fractional <1>:            Implementation Differences.
* type sizes, fractional:                Fractional Type Sizes.
* u unit:                                Measurements.
* uf request, and font styles:           Font Families.
* ul glyph, and cflags:                  Using Symbols.
* ul request, and font translations:     Changing Fonts.
* Ultrix-specific man macros:            Optional man extensions.
* unary operators:                       Expressions.
* unbreakable space:                     Page Motions.
* undefined identifiers:                 Identifiers.
* undefined request:                     Comments.
* underline font (uf):                   Artificial Fonts.
* underlining (ul):                      Artificial Fonts.
* underlining, continuous (cu):          Artificial Fonts.
* underscore glyph (\[ru]):              Drawing Requests.
* unformatting diversions (asciify):     Diversions.
* unformatting horizontal space:         Strings.
* Unicode <1>:                           Using Symbols.
* Unicode:                               Identifiers.
* unit, c:                               Measurements.
* unit, f:                               Measurements.
* unit, f, and colors:                   Colors.
* unit, i:                               Measurements.
* unit, M:                               Measurements.
* unit, m:                               Measurements.
* unit, n:                               Measurements.
* unit, P:                               Measurements.
* unit, p:                               Measurements.
* unit, s <1>:                           Fractional Type Sizes.
* unit, s:                               Measurements.
* unit, u:                               Measurements.
* unit, v:                               Measurements.
* unit, z <1>:                           Fractional Type Sizes.
* unit, z:                               Measurements.
* units of measurement:                  Measurements.
* units, default:                        Default Units.
* unnamed fill colors (\D'F...'):        Drawing Requests.
* unnamed glyphs:                        Using Symbols.
* unnamed glyphs, accessing with \N:     Font File Format.
* unsafe mode <1>:                       I/O.
* unsafe mode <2>:                       Macro Directories.
* unsafe mode:                           Groff Options.
* user's macro tutorial:                 Tutorial for Macro Users.
* user's tutorial for macros:            Tutorial for Macro Users.
* using symbols:                         Using Symbols.
* utf-8, output encoding:                Groff Options.
* v unit:                                Measurements.
* valid numeric expression:              Expressions.
* value, incrementing without changing the register: Auto-increment.
* variables in environment:              Environment.
* version number, major, register (.x):  Built-in Registers.
* version number, minor, register (.y):  Built-in Registers.
* vertical line drawing (\L):            Drawing Requests.
* vertical line spacing register (.v):   Changing Type Sizes.
* vertical line spacing, changing (vs):  Changing Type Sizes.
* vertical line spacing, effective value: Changing Type Sizes.
* vertical motion (\v):                  Page Motions.
* vertical page location, marking (mk):  Page Motions.
* vertical page location, returning to marked (rt): Page Motions.
* vertical position in diversion register (.d): Diversions.
* vertical position trap enable register (.vpt): Page Location Traps.
* vertical position traps, enabling (vpt): Page Location Traps.
* vertical resolution:                   DESC File Format.
* vertical resolution register (.V):     Built-in Registers.
* vertical space unit (v):               Measurements.
* vertical spacing:                      Sizes.
* warnings <1>:                          Warnings.
* warnings:                              Debugging.
* warnings, level (warn):                Debugging.
* what is groff?:                        What Is groff?.
* while:                                 while.
* while request, and the ! operator:     Expressions.
* while request, confusing with br:      while.
* while request, operators to use with:  Operators in Conditionals.
* whitespace characters:                 Identifiers.
* width escape (\w):                     Page Motions.
* width, of last glyph (.w):             Environments.
* word space size register (.ss):        Manipulating Filling and Adjusting.
* writing macros:                        Writing Macros.
* writing to file (write):               I/O.
* year, current, register (year, yr):    Built-in Registers.
* z unit <1>:                            Fractional Type Sizes.
* z unit:                                Measurements.
* zero width space character (\&) <1>:   Drawing Requests.
* zero width space character (\&) <2>:   Ligatures and Kerning.
* zero width space character (\&):       Requests.
* zero-width printing (\z, \Z):          Page Motions.
* |, and page motion:                    Expressions.


