драйвер вывода groff для пишущих (оконечных) устройств (groff output driver for typewriter-like (terminal) devices)
Имя (Name)
grotty - groff output driver for typewriter-like (terminal)
devices
Синопсис (Synopsis)
grotty [-dfho] [-i|-r] [-F dir] [file ...]
grotty -c [-bBdfhouU] [-F dir] [file ...]
grotty --help
grotty -v
grotty --version
Описание (Description)
The GNU roff TTY ('Teletype') output driver translates the output
of troff(1) into a form suitable for typewriter-like devices,
including terminal emulators. Normally, grotty is invoked by
groff(1) when the latter is given one of the -Tascii, -Tlatin1,
or -Tutf8 options on systems using ISO character encoding
standards, or with -Tcp1047 or -Tutf8 on EBCDIC-based hosts. If
no file arguments are given, or if file is '-', grotty reads the
standard input stream. Output is written to the standard output
stream.
By default, grotty emits SGR escape sequences (from ISO 6429,
popularly called 'ANSI escapes') to change text attributes (bold,
italic, underline, reverse-video, and colors). Devices
supporting the appropriate sequences can view roff documents
using eight different background and foreground colors.
In keeping with long-standing practice and the rarity of
terminals, hardware or emulated, that support oblique or italic
fonts, italicized text is represented with underlining by
default—but see the -i option below.
Following ISO 6429, the following colors are defined in tty.tmac:
black, white, red, green, blue, yellow, magenta, and cyan.
Unrecognized colors are mapped to the default color, which is
dependent on the settings of the terminal.
SGR support in pagers
When paging grotty's output with less(1), the latter program must
be instructed to pass SGR sequences through to the device; its -R
option is one way to achieve this. Consequently, programs like
man(1) which page roff documents with less must call it with an
appopriate option.
Legacy output format
The -c option tells grotty to use an output format compatible
with paper terminals, like the Teletype machines for which roff
and nroff were first developed but which are no longer in wide
use. SGR escape sequences are not emitted. Instead, grotty
overstrikes, representing a bold character c with the sequence
'c BACKSPACE c' an italic character c with the sequence
'_ BACKSPACE c', and bold italics with '_ BACKSPACE c
BACKSPACE c'. Furthermore, color output is disabled. The same
effect can be achieved either by setting the GROFF_NO_SGR
environment variable or by using a groff escape sequence within
the document; see subsection 'Device control commands', below.
The legacy output format can be rendered on a video terminal (or
emulator) by piping grotty's output through ul(1), which may
render bold italics as reverse video. Some implementations of
more(1) are also able to display these sequences; you may wish to
experiment with that command's -b option. less renders legacy
bold and italics without requiring options. In contrast to the
terminal output drivers of some other roff implementations,
grotty never outputs reverse line feeds. There is therefore no
need to filter its output through col(1).
Device control commands
grotty understands a single device control function produced
using the roff \X escape sequence in a document.
\X'tty: sgr [n]'
If n is non-zero or missing, enable SGR sequences (this is
the default); otherwise, use the legacy output format.
Device description files
If DESC file for the character encoding contains the keyword
'unicode', grotty emits Unicode characters in UTF-8 encoding.
Otherwise, it emits characters in a single-byte encoding
depending on the data in the font description files. See
groff_font(5) for more details.
A font description file may contain a command 'internalname n'
where n is a decimal integer. If the 01 bit in n is set, then
the font is treated as an italic font; if the 02 bit is set, then
it is treated as a bold font.
Параметры (Options)
--help displays a usage message, while -v and --version show
version information; all exit afterward.
-b Suppress the use of overstriking for bold characters.
Ignored if -c isn't used.
-B Use only overstriking for bold-italic characters. Ignored
if -c isn't used.
-c Use grotty's legacy output format (see subsection 'Legacy
output format' above).
-d Ignore all \D roff escapes (draw commands). By default,
grotty renders \D'l...' commands that have at least one
zero argument (and so are either horizontal or vertical)
using Unicode box drawing characters (for the 'utf8'
device) or the -, |, and + characters (for all other
devices). In a similar way, grotty handles \D'p...'
commands which consist entirely of horizontal and vertical
lines.
-f Use form feeds in the output. A form feed is output at
the end of each page that has no output on its last line.
-F dir Prepend directory dir/devname to the search path for font
and device description files; name describes the output
device's character encoding, one of ascii, latin1, utf8,
or cp1047.
-h Use literal horizontal tab characters in the output. Tabs
are assumed to be set every 8 columns.
-i Render italic-styled text (fonts 'I' and 'BI') with the
SGR attribute for italic text rather than underlined text.
Note that many terminals don't support this attribute;
however, xterm(1), since patch #314 (2014-12-28), does.
Ignored if -c is also specified.
-o Suppress overstriking (other than for bold and/or
underlined characters when the legacy output format is in
use).
-r Render italic-styled text (fonts 'I' and 'BI') with the
SGR attribute for reverse-video text rather than
underlined text. Ignored if -c or -i is also specified.
-u Suppress the use of underlining for italic characters.
Ignored if -c isn't used.
-U Use only underlining for bold-italic characters. Ignored
if -c isn't used.
Окружение (Environment)
GROFF_FONT_PATH
A list of directories in which to seek the selected output
device's directory of device and font description files.
See troff(1) and groff_font(5).
GROFF_NO_SGR
If set, grotty's legacy output format is used; see
subsection 'Legacy output format' above.
Файлы (Files)
/usr/local/share/groff/1.23.0/font/devascii/DESC
Device description file for the 'ascii' device.
/usr/local/share/groff/1.23.0/font/devascii/F
Font description file for font F of the 'ascii' device.
/usr/local/share/groff/1.23.0/font/devcp1047/DESC
Device description file for the 'cp1047' device.
/usr/local/share/groff/1.23.0/font/devcp1047/F
Font description file for font F of the 'cp1047' device.
/usr/local/share/groff/1.23.0/font/devlatin1/DESC
Device description file for the 'latin1' device.
/usr/local/share/groff/1.23.0/font/devlatin1/F
Font description file for font F of the 'latin1' device.
/usr/local/share/groff/1.23.0/font/devutf8/DESC
Device description file for the 'utf8' device.
/usr/local/share/groff/1.23.0/font/devutf8/F
Font description file for font F of the 'utf8' device.
/usr/local/share/groff/1.23.0/tmac/tty.tmac
Macros for use with grotty.
/usr/local/share/groff/1.23.0/tmac/tty-char.tmac
Additional character definitions for use with grotty.
Ошибки (баги) (Bugs)
grotty is intended only for simple documents.
There is no support for fractional horizontal or vertical
motions.
There is no support for the roff \D escape sequence (draw
command) other than horizontal and vertical lines.
Characters above the first line (i.e., with a vertical position
of 0) cannot be printed.
Color handling differs from grops(1). The groff \M escape
sequence doesn't set the fill color for closed graphic objects
(which grotty doesn't support anyway) but instead changes the
background color of the character cell, affecting all subsequent
operations.
Примеры (Examples)
The following groff document exercises several features, not all
of which may be supported by a given output device: (1) bold
style; (2) italic (underline) style; (3) bold-italic style;
(4) character composition by overstriking ('coöperate');
(5) foreground color; (6) background color; and (7) horizontal
and vertical line-drawing.
You might see \f[B]bold\f[] and \f[I]italic\f[].
Some people see \f[BI]both\f[].
If the output device does (not) co\z\[ad]operate,
you might see \m[red]red\m[].
Black on cyan can have a \M[cyan]\m[black]prominent\m[]\M[]
\D'l 1i 0'\D'l 0 2i'\D'l 1i 0' look.
.\" If in nroff mode, end page now.
.if n .pl \n[nl]u
Compare and contrast the output of the following:
$ nroff file
$ groff -T ascii file
$ groff -T utf8 -Z file | grotty -i
$ groff -T utf8 -Z file | grotty -c | ul
Note that the example file above is a 'raw' groff document, not a
man page. Use of color escapes in man pages is strongly
discouraged. Some implementations of man(1) completely disable
them. See subsection 'Portability' of groff_man_style(7) for
guidance on writing man pages that are viewable by as many
readers as possible.
Смотри также (See also)
'Control Functions for Coded Character Sets' (ECMA-48)
5th edition, Ecma International, June 1991. A gratis version of
ISO 6429, this document includes a normative description of SGR
escape sequences. Available at
⟨http://www.ecma-international.org/publications/files/ECMA-ST/
Ecma-048.pdf⟩.
groff(1), troff(1), groff_out(5), groff_font(5), groff_char(7),
ul(1), more(1), less(1), man(1)
