.\" Copyright (C) 2014 Marko Myllynen <myllynen@redhat.com>
.\"
.\" SPDX-License-Identifier: GPL-2.0-or-later
.\"
.TH iconv 1 2024-05-02 "Linux man-pages (unreleased)"
.SH NAME
iconv \- convert text from one character encoding to another
.SH SYNOPSIS
.B iconv
.RI [ options ]
.RI "[\-f " from-encoding "]"
.RI "[\-t " to-encoding "]"
.RI [ inputfile ]...
.SH DESCRIPTION
The
.B 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 (\-),
.B iconv
reads from standard input.
If no output file is given,
.B iconv
writes to standard output.
.P
If no
.I from-encoding
is given, the default is derived
from the current locale's character encoding.
If no
.I to-encoding
is given, the default is derived
from the current locale's character
encoding.
.SH OPTIONS
.TP
.BI \-\-from\-code= from-encoding
.TQ
.BI \-f\~ from-encoding
Use
.I from-encoding
for input characters.
.TP
.BI \-\-to\-code= to-encoding
.TQ
.BI \-t\~ to-encoding
Use
.I to-encoding
for output characters.
.IP
If the string
.B //IGNORE
is appended to
.IR to-encoding ,
characters that cannot be converted are discarded and an error is
printed after conversion.
.IP
If the string
.B //TRANSLIT
is appended to
.IR 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.
.TP
.B \-\-list
.TQ
.B \-l
List all known character set encodings.
.TP
.B \-c
Silently discard characters that cannot be converted instead of
terminating when encountering such characters.
.TP
.BI \-\-output= outputfile
.TQ
.BI \-o\~ outputfile
Use
.I outputfile
for output.
.TP
.B \-\-silent
.TQ
.B \-s
This option is ignored; it is provided only for compatibility.
.TP
.B \-\-verbose
Print progress information on standard error when processing
multiple files.
.TP
.B \-\-help
.TQ
.B \-?
Print a usage summary and exit.
.TP
.B \-\-usage
Print a short usage summary and exit.
.TP
.B \-\-version
.TQ
.B \-V
Print the version number, license, and disclaimer of warranty for
.BR iconv .
.SH EXIT STATUS
Zero on success, nonzero on errors.
.SH ENVIRONMENT
Internally, the
.B iconv
program uses the
.BR iconv (3)
function which in turn uses
.I gconv
modules (dynamically loaded shared libraries)
to convert to and from a character set.
Before calling
.BR iconv (3),
the
.B iconv
program must first allocate a conversion descriptor using
.BR iconv_open (3).
The operation of the latter function is influenced by the setting of the
.B GCONV_PATH
environment variable:
.IP \[bu] 3
If
.B GCONV_PATH
is not set,
.BR iconv_open (3)
loads the system gconv module configuration cache file created by
.BR 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.
.IP \[bu]
If
.B GCONV_PATH
is defined (as a colon-separated list of pathnames),
the system gconv module configuration cache is not used.
Instead,
.BR iconv_open (3)
first tries to load the configuration files by searching the directories in
.B 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
.B GCONV_PATH
is used.
This allows users to use custom modules and even replace system-provided
modules by providing such modules in
.B GCONV_PATH
directories.
.SH FILES
.TP
.I /usr/lib/gconv
Usual default gconv module path.
.TP
.I /usr/lib/gconv/gconv\-modules
Usual system default gconv module configuration file.
.TP
.I /usr/lib/gconv/gconv\-modules.cache
Usual system gconv module configuration cache.
.P
Depending on the architecture,
the above files may instead be located at directories with the path prefix
.IR /usr/lib64 .
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2001.
.SH EXAMPLES
Convert text from the ISO/IEC\~8859-15 character encoding to UTF-8:
.P
.in +4n
.EX
$ \fBiconv \-f ISO\-8859\-15 \-t UTF\-8 < input.txt > output.txt\fP
.EE
.in
.P
The next example converts from UTF-8 to ASCII, transliterating when
possible:
.P
.in +4n
.EX
$ \fBecho abc ß α € àḃç | iconv \-f UTF\-8 \-t ASCII//TRANSLIT\fP
abc ss ? EUR abc
.EE
.in
.SH SEE ALSO
.BR locale (1),
.BR uconv (1),
.BR iconv (3),
.BR nl_langinfo (3),
.BR charsets (7),
.BR iconvconfig (8)