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ICONV(1) Linux User Manual ICONV(1)

iconv - convert text from one character encoding to another

iconv [options] [-f from-encoding] [-t to-encoding] [inputfile]...

The iconv program reads in text in one encoding and outputs the text in another encoding. If no input files are given, or if it is given as a dash (-), iconv reads from standard input. If no output file is given, iconv writes to standard output.

If no from-encoding is given, the default is derived from the current locale's character encoding. If no to-encoding is given, the default is derived from the current locale's character encoding.

-f from-encoding, --from-code=from-encoding
Use from-encoding for input characters.
-t to-encoding, --to-code=to-encoding
Use to-encoding for output characters.
If the string //IGNORE is appended to to-encoding, characters that cannot be converted are discarded and an error is printed after conversion.
If the string //TRANSLIT is appended to to-encoding, characters being converted are transliterated when needed and possible. This means that when a character cannot be represented in the target character set, it can be approximated through one or several similar looking characters. Characters that are outside of the target character set and cannot be transliterated are replaced with a question mark (?) in the output.
-l, --list
List all known character set encodings.
-c
Silently discard characters that cannot be converted instead of terminating when encountering such characters.
-o outputfile, --output=outputfile
Use outputfile for output.
-s, --silent
This option is ignored; it is provided only for compatibility.
--verbose
Print progress information on standard error when processing multiple files.
-?, --help
Print a usage summary and exit.
--usage
Print a short usage summary and exit.
-V, --version
Print the version number, license, and disclaimer of warranty for iconv.

Zero on success, nonzero on errors.

Internally, the iconv program uses the iconv(3) function which in turn uses gconv modules (dynamically loaded shared libraries) to convert to and from a character set. Before calling iconv(3), the iconv program must first allocate a conversion descriptor using iconv_open(3). The operation of the latter function is influenced by the setting of the GCONV_PATH environment variable:
  • If GCONV_PATH is not set, iconv_open(3) loads the system gconv module configuration cache file created by iconvconfig(8) and then, based on the configuration, loads the gconv modules needed to perform the conversion. If the system gconv module configuration cache file is not available then the system gconv module configuration file is used.
  • If GCONV_PATH is defined (as a colon-separated list of pathnames), the system gconv module configuration cache is not used. Instead, iconv_open(3) first tries to load the configuration files by searching the directories in GCONV_PATH in order, followed by the system default gconv module configuration file. If a directory does not contain a gconv module configuration file, any gconv modules that it may contain are ignored. If a directory contains a gconv module configuration file and it is determined that a module needed for this conversion is available in the directory, then the needed module is loaded from that directory, the order being such that the first suitable module found in GCONV_PATH is used. This allows users to use custom modules and even replace system-provided modules by providing such modules in GCONV_PATH directories.

/usr/lib/gconv
Usual default gconv module path.
/usr/lib/gconv/gconv-modules
Usual system default gconv module configuration file.
/usr/lib/gconv/gconv-modules.cache
Usual system gconv module configuration cache.

POSIX.1-2001.

Convert text from the ISO 8859-15 character encoding to UTF-8: 


$ iconv -f ISO-8859-15 -t UTF-8 < input.txt > output.txt

The next example converts from UTF-8 to ASCII, transliterating when possible:


$ echo abc ß α € àḃç | iconv -f UTF-8 -t ASCII//TRANSLIT
abc ss ? EUR abc

locale(1), uconv(1), iconv(3), nl_langinfo(3), charsets(7), iconvconfig(8)

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2019-03-06 GNU