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(emacs)Enabling Multibyte

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Enabling Multibyte Characters
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   You can enable or disable multibyte character support, either for
Emacs as a whole, or for a single buffer.  When multibyte characters are
disabled in a buffer, then each byte in that buffer represents a
character, even codes 0200 through 0377.  The old features for
supporting the European character sets, ISO Latin-1 and ISO Latin-2,
work as they did in Emacs 19 and also work for the other ISO 8859
character sets.

   However, there is no need to turn off multibyte character support to
use ISO Latin; the Emacs multibyte character set includes all the
characters in these character sets, and Emacs can translate
automatically to and from the ISO codes.

   By default, Emacs starts in multibyte mode, because that allows you
to use all the supported languages and scripts without limitations.

   To edit a particular file in unibyte representation, visit it using
`find-file-literally'.  Note: Visiting.  To convert a buffer in
multibyte representation into a single-byte representation of the same
characters, the easiest way is to save the contents in a file, kill the
buffer, and find the file again with `find-file-literally'.  You can
also use `C-x <RET> c' (`universal-coding-system-argument') and specify
`raw-text' as the coding system with which to find or save a file.
Note: Specify Coding.  Finding a file as `raw-text' doesn't disable
format conversion, uncompression and auto mode selection as
`find-file-literally' does.

   To turn off multibyte character support by default, start Emacs with
the `--unibyte' option (Note: Initial Options), or set the
environment variable `EMACS_UNIBYTE'.  You can also customize
`enable-multibyte-characters' or, equivalently, directly set the
variable `default-enable-multibyte-characters' to `nil' in your init
file to have basically the same effect as `--unibyte'.

   To convert a unibyte session to a multibyte session, set
`default-enable-multibyte-characters' to `t'.  Buffers which were
created in the unibyte session before you turn on multibyte support
will stay unibyte.  You can turn on multibyte support in a specific
buffer by invoking the command `toggle-enable-multibyte-characters' in
that buffer.

   With `--unibyte', multibyte strings are not created during
initialization from the values of environment variables, `/etc/passwd'
entries etc. that contain non-ASCII 8-bit characters.

   Emacs normally loads Lisp files as multibyte, regardless of whether
you used `--unibyte'.  This includes the Emacs initialization file,
`.emacs', and the initialization files of Emacs packages such as Gnus.
However, you can specify unibyte loading for a particular Lisp file, by
putting `-*-unibyte: t;-*-' in a comment on the first line.  Then that
file is always loaded as unibyte text, even if you did not start Emacs
with `--unibyte'.  The motivation for these conventions is that it is
more reliable to always load any particular Lisp file in the same way.
However, you can load a Lisp file as unibyte, on any one occasion, by
typing `C-x <RET> c raw-text <RET>' immediately before loading it.

   The mode line indicates whether multibyte character support is
enabled in the current buffer.  If it is, there are two or more
characters (most often two dashes) before the colon near the beginning
of the mode line.  When multibyte characters are not enabled, just one
dash precedes the colon.