NAME
luit - Locale and ISO 2022 support for Unicode
terminals
SYNOPSIS
luit [ options ] [ -- ] [
program [ args ] ]
DESCRIPTION
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.
Luit is usually invoked transparently by the terminal
emulator. For information about running luit from the
command line, see EXAMPLES below.
OPTIONS
- -h
- Display some summary help and quit.
- -list
- List the supported charsets and encodings, then quit.
- -v
- Be verbose.
- -c
- Function as a simple converter from standard input to standard
output.
- -x
- Exit as soon as the child dies. This may cause luit to
loose data at the end of the child's output.
- -argv0 name
- Set the child's name (as passed in argv[0]).
- -encoding encoding
- Set up luit to use encoding rather than the
current locale's encoding.
- +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.
- +kssgr
- Use GL codes after a single shift for keyboard input. By
default, GR codes are generated after a single shift when
generating eight-bit 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.
EXAMPLES
The most typical use of luit is to adapt an
instance of XTerm to the locale's encoding. Current versions
of XTerm invoke luit automatically when it is needed.
If you are using an older release of XTerm, or a different
terminal emulator, you may invoke luit manually:
- $ xterm -u8 -e luit
If you are running in a UTF-8 locale but need to access a remote
machine that doesn't support UTF-8, luit can adapt the
remote output to your terminal:
- $ LC_ALL=fr_FR luit ssh legacy-machine
Luit is also useful with applications that hard-wire an
encoding that is different from the one normally used on the system
or want to use legacy escape sequences for multilingual output. In
particular, versions of Emacs that do not speak UTF-8 well
can use luit for multilingual output:
- $ luit -encoding 'ISO 8859-1' emacs -nw
And then, in Emacs,
- M-x set-terminal-coding-system RET iso-2022-8bit-ss2 RET
FILES
- /usr/lib/X11/fonts/encodings/encodings.dir
- The system-wide encodings directory.
- /usr/lib/X11/locale/locale.alias
- The file mapping locales to locale encodings.
SECURITY
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
cannot safely drop privileges.
BUGS
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.
SEE ALSO
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).
AUTHOR
The version of Luit included in this X.org
Foundataion release was originally written by Juliusz Chroboczek
<jch@freedesktop.org> for the
XFree86 Project.