uconv Man page

UCONV(1) ICU 55.1 Manual UCONV(1)

NAME

uconv – convert data from one encoding to another

SYNOPSIS

uconv [ -h, -?, –help ] [ -V, –version ] [ -s, –silent ] [ -v,
–verbose ] [ -l, –list | -l, –list-code code | –default-code | -L,
–list-transliterators ] [ –canon ] [ -x transliteration ] [
–to-callback callback | -c ] [ –from-callback callback | -i ] [
–callback callback ] [ –fallback | –no-fallback ] [ -b, –block-size
size ] [ -f, –from-code encoding ] [ -t, –to-code encoding ] [
–add-signature ] [ –remove-signature ] [ -o, –output file ] [
file… ]

DESCRIPTION

uconv converts, or transcodes, each given file (or its standard input
if no file is specified) from one encoding to another. The transcoding
is done using Unicode as a pivot encoding (i.e. the data are first
transcoded from their original encoding to Unicode, and then from Uni‐
code to the destination encoding).

If an encoding is not specified or is -, the default encoding is used.
Thus, calling uconv with no encoding provides an easy way to validate
and sanitize data files for further consumption by tools requiring data
in the default encoding.

When calling uconv, it is possible to specify callbacks that are used
to handle invalid characters in the input, or characters that cannot be
transcoded to the destination encoding. Some encodings, for example,
offer a default substitution character that can be used to represent
the occurence of such characters in the input. Other callbacks offer a
useful visual representation of the invalid data.

uconv can also run the specified transliteration on the transcoded
data, in which case transliteration will happen as an intermediate
step, after the data have been transcoded to Unicode. The translitera‐
tion can be either a list of semicolon-separated transliterator names,
or an arbitrarily complex set of rules in the ICU transliteration rules
format.

For transcoding purposes, uconv options are compatible with those of
iconv, making it easy to replace it in scripts. It is not necessar‐
ily the case, however, that the encoding names used by uconv and ICU
are the same as the ones used by iconv. Also, options that provide
informational data, such as the -l, –list one offered by some iconv
variants such as GNU’s, produce data in a slightly different and easier
to parse format.

OPTIONS

-h, -?, –help
Print help about usage and exit.

-V, –version
Print the version of uconv and exit.

-s, –silent
Suppress messages during execution.

-v, –verbose
Display extra informative messages during execution.

-l, –list
List all the available encodings and exit.

-l, –list-code code
List only the code encoding and exit. If code is not a proper
encoding, exit with an error.

–default-code
List only the name of the default encoding and exit.

-L, –list-transliterators
List all the available transliterators and exit.

–canon
If used with -l, –list or –default-code, the list of encodings
is produced in a format compatible with convrtrs.txt(5). If
used with -L, –list-transliterators, print only one transliter‐
ator name per line.

-x transliteration
Run the given transliteration on the transcoded Unicode data,
and use the transliterated data as input for the transcoding to
the the destination encoding.

–to-callback callback
Use callback to handle characters that cannot be transcoded to
the destination encoding. See section CALLBACKS for details on
valid callbacks.

-c Omit invalid characters from the output. Same as –to-callback
skip.

–from-callback callback
Use callback to handle characters that cannot be transcoded from
the original encoding. See section CALLBACKS for details on
valid callbacks.

-i Ignore invalid sequences in the input. Same as –from-callback
skip.

–callback callback
Use callback to handle both characters that cannot be transcoded
from the original encoding and characters that cannot be
transcoded to the destination encoding. See section CALLBACKS
for details on valid callbacks.

–fallback
Use the fallback mapping when transcoding from Unicode to the
destination encoding.

–no-fallback
Do not use the fallback mapping when transcoding from Unicode to
the destination encoding. This is the default.

-b, –block-size size
Read input in blocks of size bytes at a time. The default block
size is 4096.

-f, –from-code encoding
Set the original encoding of the data to encoding.

-t, –to-code encoding
Transcode the data to encoding.

–add-signature
Add a U+FEFF Unicode signature character (BOM) if the output
charset supports it and does not add one anyway.

–remove-signature
Remove a U+FEFF Unicode signature character (BOM).

-o, –output file
Write the transcoded data to file.

CALLBACKS
uconv supports specifying callbacks to handle invalid data. Callbacks
can be set for both directions of transcoding: from the original encod‐
ing to Unicode, with the –from-callback option, and from Unicode to
the destination encoding, with the –to-callback option.

The following is a list of valid callback names, along with a descrip‐
tion of their behavior. The list of callbacks actually supported by
uconv is displayed when it is called with -h, –help.

substitute Write the the encoding’s substitute sequence, or the
Unicode replacement character U+FFFD when transcoding
to Unicode.

skip Ignore the invalid data.

stop Stop with an error when encountering invalid data.
This is the default callback.

escape Same as escape-icu.

escape-icu Replace the missing characters with a string of the
format %Uhhhh for plane 0 characters, and %Uhhhh%Uhhhh
for planes 1 and above characters, where hhhh is the
hexadecimal value of one of the UTF-16 code units rep‐
resenting the character. Characters from planes 1 and
above are written as a pair of UTF-16 surrogate code
units.

escape-java Replace the missing characters with a string of the
format \uhhhh for plane 0 characters, and \uhhhh\uhhhh
for planes 1 and above characters, where hhhh is the
hexadecimal value of one of the UTF-16 code units rep‐
resenting the character. Characters from planes 1 and
above are written as a pair of UTF-16 surrogate code
units.

escape-c Replace the missing characters with a string of the
format \uhhhh for plane 0 characters, and \Uhhhhhhhh
for planes 1 and above characters, where hhhh and hhh‐
hhhhh are the hexadecimal values of the Unicode code‐
point.

escape-xml Same as escape-xml-hex.

escape-xml-hex Replace the missing characters with a string of the
format &#xhhhh;, where hhhh is the hexadecimal value
of the Unicode codepoint.

escape-xml-dec Replace the missing characters with a string of the
format &#nnnn;, where nnnn is the decimal value of the
Unicode codepoint.

escape-unicode Replace the missing characters with a string of the
format {U+hhhh}, where hhhh is the hexadecimal value
of the Unicode codepoint. That hexadecimal string is
of variable length and can use from 4 to 6 digits.
This is the format universally used to denote a Uni‐
code codepoint in the litterature, delimited by curly
braces for easy recognition of those substitutions in
the output.

EXAMPLES
Convert data from a given encoding to the platform encoding:

$ uconv -f encoding

Check if a file contains valid data for a given encoding:

$ uconv -f encoding -c file >/dev/null

Convert a UTF-8 file to a given encoding and ensure that the resulting
text is good for any version of HTML:

$ uconv -f utf-8 -t encoding \
–callback escape-xml-dec file

Display the names of the Unicode code points in a UTF-file:

$ uconv -f utf-8 -x any-name file

Print the name of a Unicode code point whose value is known (U+30AB in
this example):

$ echo ‘\u30ab’ | uconv -x ‘hex-any; any-name’; echo
{KATAKANA LETTER KA}{LINE FEED}
$

(The names are delimited by curly braces. Also, the name of the line
terminator is also displayed.)

Normalize UTF-8 data using Unicode NFKC, remove all control characters,
and map Katakana to Hiragana:

$ uconv -f utf-8 -t utf-8 \
-x ‘::nfkc; [:Cc:] >; ::katakana-hiragana;’

CAVEATS AND

BUGS

uconv does report errors as occuring at the first invalid byte encoun‐
tered. This may be confusing to users of GNU iconv, which reports
errors as occuring at the first byte of an invalid sequence. For multi-
byte character sets or encodings, this means that uconv error positions
may be at a later offset in the input stream than would be the case
with GNU iconv.

The reporting of error positions when a transliterator is used may be
inaccurate or unavailable, in which case uconv will report the offset
in the output stream at which the error occured.

AUTHORS
Jonas Utterstroem
Yves Arrouye

VERSION
55.1

COPRYRIGHT

Copyright (C) 2000-2005 IBM, Inc. and others.

SEE ALSO

iconv

ICU MANPAGE 2005-jul-1 UCONV(1)

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