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luit - Locale and ISO 2022 support for Unicode terminals
luit
[ options ] [ -- ] [ program [ args ] ]
Luit is a filter that
can be run between an arbitrary application and a UTF-8 terminal emulator.
It will convert application output from the locale's encoding into UTF-8,
and convert terminal input from UTF-8 into the locale's encoding.
An application
may also request switching to a different output encoding using ISO 2022
and ISO 6429 escape sequences. Use of this feature is discouraged: multilingual
applications should be modified to directly generate UTF-8 instead.
- -h
- Display some summary help and quit.
- -list
- List the supported charsets and
quit.
- -v
- Be verbose.
- -c
- Function as a simple converter from standard input
to standard output.
- -argv0 name
- Set the child's name (as passed in argv[0]).
- +oss
- Disable interpretation of single shifts in application output.
- +ols
- Disable interpretation of locking shifts in application output.
- +osl
- Disable
interpretation of character set selection sequences in application output.
- +ot
- Disable interpretation of all sequences and pass all sequences in application
output to the terminal unchanged. This may lead to interesting results.
- -k7
- Generate seven-bit characters for keyboard input.
- +kss
- Disable generation
of single-shifts for keyboard input.
- -kls
- Generate locking shifts (SO/SI)
for keyboard input.
- -gl gn
- Set the initial assignment of GL. The argument
should be one of g0, g1, g2 or g3. The default depends on the locale, but
is usually g0.
- -gr gk
- Set the initial assignment of GR. The default depends
on the locale, and is usually g2 except for EUC locales, where it is g1.
- -g0 charset
- Set the charset initially selected in G0. The default depends
on the locale, but is usually ASCII.
- -g1 charset
- Set the charset initially
selected in G1. The default depends on the locale.
- -g2 charset
- Set the charset
initially selected in G2. The default depends on the locale.
- -g3 charset
- Set the charset initially selected in G3. The default depends on the locale.
- -ilog filename
- Log into filename all the bytes received from the child.
- -olog
filename
- Log into filename all the bytes sent to the terminal emulator.
- --
- End of options.
The most typical use of luit is to adapt an instance
of XTerm in UTF-8 mode to the locale's encoding. For most locales, this doesn't
require using any flags:
- $ xterm -u8 -e luit
Luit may also be used with
applications that hard-wire an encoding that is different from the one normally
used on the system. In order to use such applications, you will need to
directly manipulate luit's ISO 2022 state:
- $ xterm -u8 -e luit -g2 'CP 1252'
The
-v flag may be used in order to examine luit's initial state.
Future versions
of XTerm will automatically invoke luit when necessary.
- /usr/X11R6/lib/X11/fonts/encodings/encodings.dir
- The system-wide encodings directory.
- /usr/X11R6/lib/X11/locale/locale.alias
- The file mapping locales to locale encodings.
On systems with
SVR4 (``Unix-98'') ptys (Linux version 2.2 and later, SVR4), luit should be run
as the invoking user.
On systems without SVR4 (``Unix-98'') ptys (notably BSD
variants), running luit as an ordinary user will leave the tty world-writable;
this is a security hole, and luit will generate a warning (but still accept
to run). A possible solution is to make luit suid root; luit should drop
privileges sufficiently early to make this safe. However, the startup code
has not been exhaustively audited, and the author takes no responsibility
for any resulting security issues.
Luit will refuse to run if it is installed
setuid and the underlying system does not have POSIX saved ids.
None
of this complexity should be necessary. Stateless UTF-8 throughout the system
is the way to go.
Charsets with a non-trivial intermediary byte are not
yet supported.
Selecting alternate sets of control characters is not supported
and will never be.
xterm(1)
, unicode(7)
, utf-8(7)
, charsets(7)
. Character
Code Structure and Extension Techniques (ISO 2022, ECMA-35). Control Functions
for Coded Character Sets (ISO 6429, ECMA-48).
Luit was written by Juliusz
Chroboczek <[email protected]> for the XFree86 project.
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