ICONV(1P) POSIX Programmer's Manual ICONV(1P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
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NAMEiconv - codeset conversion
SYNOPSISiconv [-cs] -f frommap -t tomap [file ...]
iconv-f fromcode [-cs] [-t tocode [file ...]
iconv-t tocode [-cs] [-f fromcode] [file ...]
iconv-l
DESCRIPTION
The iconv utility shall convert the encoding of characters in file from
one codeset to another and write the results to standard output.
When the options indicate that charmap files are used to specify the
codesets (see OPTIONS), the codeset conversion shall be accomplished by
performing a logical join on the symbolic character names in the two
charmaps. The implementation need not support the use of charmap files
for codeset conversion unless the POSIX2_LOCALEDEF symbol is defined on
the system.
OPTIONS
The iconv utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
-c Omit any characters that are invalid in the codeset of the input
file from the output. When -c is not used, the results of
encountering invalid characters in the input stream (either
those that are not characters in the codeset of the input file
or that have no corresponding character in the codeset of the
output file) shall be specified in the system documentation. The
presence or absence of -c shall not affect the exit status of
iconv.
-f fromcodeset
Identify the codeset of the input file. The implementation shall
recognize the following two forms of the fromcodeset option-
argument:
fromcode
The fromcode option-argument must not contain a slash character.
It shall be interpreted as the name of one of the codeset
descriptions provided by the implementation in an unspecified
format. Valid values of fromcode are implementation-defined.
frommap
The frommap option-argument must contain a slash character. It
shall be interpreted as the pathname of a charmap file as
defined in the Base Definitions volume of IEEE Std 1003.1-2001,
Section 6.4, Character Set Description File. If the pathname
does not represent a valid, readable charmap file, the results
are undefined.
If this option is omitted, the codeset of the current locale shall be
used.
-l Write all supported fromcode and tocode values to standard out‐
put in an unspecified format.
-s Suppress any messages written to standard error concerning
invalid characters. When -s is not used, the results of encoun‐
tering invalid characters in the input stream (either those that
are not valid characters in the codeset of the input file or
that have no corresponding character in the codeset of the out‐
put file) shall be specified in the system documentation. The
presence or absence of -s shall not affect the exit status of
iconv.
-t tocodeset
Identify the codeset to be used for the output file. The imple‐
mentation shall recognize the following two forms of the tocode‐
set option-argument:
tocode
The semantics shall be equivalent to the -f fromcode option.
tomap
The semantics shall be equivalent to the tomap option.
If this option is omitted, the codeset of the current locale shall be
used.
If either -f or -t represents a charmap file, but the other does not
(or is omitted), or both -f and -t are omitted, the results are unde‐
fined.
OPERANDS
The following operand shall be supported:
file A pathname of an input file. If no file operands are specified,
or if a file operand is '-', the standard input shall be used.
STDIN
The standard input shall be used only if no file operands are speci‐
fied, or if a file operand is '-' .
INPUT FILES
The input file shall be a text file.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
iconv:
LANG Provide a default value for the internationalization variables
that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
ables for the precedence of internationalization variables used
to determine the values of locale categories.)
LC_ALL If set to a non-empty string value, override the values of all
the other internationalization variables.
LC_CTYPE
Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as
opposed to multi-byte characters in arguments). During transla‐
tion of the file, this variable is superseded by the use of the
fromcode option-argument.
LC_MESSAGES
Determine the locale that should be used to affect the format
and contents of diagnostic messages written to standard error.
NLSPATH
Determine the location of message catalogs for the processing of
LC_MESSAGES .
ASYNCHRONOUS EVENTS
Default.
STDOUT
When the -l option is used, the standard output shall contain all sup‐
ported fromcode and tocode values, written in an unspecified format.
When the -l option is not used, the standard output shall contain the
sequence of characters read from the input files, translated to the
specified codeset. Nothing else shall be written to the standard out‐
put.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
The user must ensure that both charmap files use the same symbolic
names for characters the two codesets have in common.
EXAMPLES
The following example converts the contents of file mail.x400 from the
ISO/IEC 6937:1994 standard codeset to the ISO/IEC 8859-1:1998 standard
codeset, and stores the results in file mail.local:
iconv-f IS6937 -t IS8859 mail.x400 > mail.local
RATIONALE
The iconv utility can be used portably only when the user provides two
charmap files as option-arguments. This is because a single charmap
provided by the user cannot reliably be joined with the names in a sys‐
tem-provided character set description. The valid values for fromcode
and tocode are implementation-defined and do not have to have any rela‐
tion to the charmap mechanisms. As an aid to interactive users, the -l
option was adopted from the Plan 9 operating system. It writes informa‐
tion concerning these implementation-defined values. The format is
unspecified because there are many possible useful formats that could
be chosen, such as a matrix of valid combinations of fromcode and
tocode. The -l option is not intended for shell script usage; conform‐
ing applications will have to use charmaps.
FUTURE DIRECTIONS
None.
SEE ALSO
gencat
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 ICONV(1P)
