ICONV(1)                   POSIX Programmer's Manual                  ICONV(1)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       iconv -- codeset conversion

SYNOPSIS
       iconv [[-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
       POSIX.1-2017, 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 POSIX.1-2017, 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
                 output in an unspecified format.

       -s        Suppress any messages written to standard error concerning
                 invalid characters. When -s is not used, the results of
                 encountering 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 output 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
                 implementation shall recognize the following two forms of the
                 tocodeset option-argument:

                 tocode    The semantics shall be equivalent to the -f
                           fromcode option.

                 tomap     The semantics shall be equivalent to the -f frommap
                           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
       undefined.

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
       specified, 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 POSIX.1-2017, Section 8.2, Internationalization
                 Variables 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
                 translation 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
       supported 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
       output.

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 6937:2001 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
       system-provided character set description. The valid values for
       fromcode and tocode are implementation-defined and do not have to have
       any relation to the charmap mechanisms. As an aid to interactive users,
       the -l option was adopted from the Plan 9 operating system. It writes
       information 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;
       conforming applications will have to use charmaps.

       The iconv utility may support the conversion between ASCII and EBCDIC-
       based encodings, but is not required to do so. In an XSI-compliant
       implementation, the dd utility is the only method guaranteed to support
       conversion between these two character sets.

FUTURE DIRECTIONS
       None.

SEE ALSO
       dd, gencat

       The Base Definitions volume of POSIX.1-2017, Section 6.4, Character Set
       Description File, Chapter _8, Environment Variables, Section 12.2,
       Utility Syntax Guidelines

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                             ICONV(1)
