iconv(1p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

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

PROLOG         top

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

NAME         top

       iconv — codeset conversion

SYNOPSIS         top

       iconv [-cs] -f frommap -t tomap [file...]

       iconv -f fromcode [-cs] [-t tocode] [file...]

       iconv -t tocode [-cs] [-f fromcode] [file...]

       iconv -l

DESCRIPTION         top

       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         top

       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         top

       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         top

       The standard input shall be used only if no file operands are
       specified, or if a file operand is '-'.

INPUT FILES         top

       The input file shall be a text file.

ENVIRONMENT VARIABLES         top

       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         top

       Default.

STDOUT         top

       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         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS         top

       Default.

       The following sections are informative.

APPLICATION USAGE         top

       The user must ensure that both charmap files use the same
       symbolic names for characters the two codesets have in common.

EXAMPLES         top

       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         top

       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         top

       None.

SEE ALSO         top

       dd(1p), gencat(1p)

       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         top

       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(1P)

Pages that refer to this page: gencat(1p)