1ICONV(1P) POSIX Programmer's Manual ICONV(1P)
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6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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13 iconv — codeset conversion
14
16 iconv [−cs] −f frommap −t tomap [file...]
17 iconv −f fromcode [−cs] [−t tocode] [file...]
19 iconv −t tocode [−cs] [−f fromcode] [file...]
21 iconv −l
23
25 The iconv utility shall convert the encoding of characters in file from
26 one codeset to another and write the results to standard output.
27 When the options indicate that charmap files are used to specify the
29 codesets (see OPTIONS), the codeset conversion shall be accomplished by
30 performing a logical join on the symbolic character names in the two
31 charmaps. The implementation need not support the use of charmap files
32 for codeset conversion unless the POSIX2_LOCALEDEF symbol is defined on
33 the system.
34
36 The iconv utility shall conform to the Base Definitions volume of
37 POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.
38 The following options shall be supported:
40 −c Omit any characters that are invalid in the codeset of the
42 input file from the output. When −c is not used, the results
43 of encountering invalid characters in the input stream
44 (either those that are not characters in the codeset of the
45 input file or that have no corresponding character in the
46 codeset of the output file) shall be specified in the system
47 documentation. The presence or absence of −c shall not affect
48 the exit status of iconv.
49 −f fromcodeset
51 Identify the codeset of the input file. The implementation
52 shall recognize the following two forms of the fromcodeset
53 option-argument:
54 fromcode The fromcode option-argument must not contain a
56 <slash> character. It shall be interpreted as the
57 name of one of the codeset descriptions provided by
58 the implementation in an unspecified format. Valid
59 values of fromcode are implementation-defined.
60 frommap The frommap option-argument must contain a <slash>
62 character. It shall be interpreted as the pathname
63 of a charmap file as defined in the Base Defini‐
64 tions volume of POSIX.1‐2008, Section 6.4, Charac‐
65 ter Set Description File. If the pathname does not
66 represent a valid, readable charmap file, the
67 results are undefined.
68 If this option is omitted, the codeset of the current locale
70 shall be used.
71 −l Write all supported fromcode and tocode values to standard
73 output in an unspecified format.
74 −s Suppress any messages written to standard error concerning
76 invalid characters. When −s is not used, the results of
77 encountering invalid characters in the input stream (either
78 those that are not valid characters in the codeset of the
79 input file or that have no corresponding character in the
80 codeset of the output file) shall be specified in the system
81 documentation. The presence or absence of −s shall not affect
82 the exit status of iconv.
83 −t tocodeset
85 Identify the codeset to be used for the output file. The
86 implementation shall recognize the following two forms of the
87 tocodeset option-argument:
88 tocode The semantics shall be equivalent to the −f from‐
90 code option.
91 tomap The semantics shall be equivalent to the −f frommap
93 option.
94 If this option is omitted, the codeset of the current locale
96 shall be used.
97 If either −f or −t represents a charmap file, but the other does not
99 (or is omitted), or both −f and −t are omitted, the results are unde‐
100 fined.
101
103 The following operand shall be supported:
104 file A pathname of an input file. If no file operands are speci‐
106 fied, or if a file operand is '−', the standard input shall
107 be used.
108
110 The standard input shall be used only if no file operands are speci‐
111 fied, or if a file operand is '−'.
112
114 The input file shall be a text file.
115
117 The following environment variables shall affect the execution of
118 iconv:
119 LANG Provide a default value for the internationalization vari‐
121 ables that are unset or null. (See the Base Definitions vol‐
122 ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
123 ables for the precedence of internationalization variables
124 used to determine the values of locale categories.)
125 LC_ALL If set to a non-empty string value, override the values of
127 all the other internationalization variables.
128 LC_CTYPE Determine the locale for the interpretation of sequences of
130 bytes of text data as characters (for example, single-byte as
131 opposed to multi-byte characters in arguments). During trans‐
132 lation of the file, this variable is superseded by the use of
133 the fromcode option-argument.
134 LC_MESSAGES
136 Determine the locale that should be used to affect the format
137 and contents of diagnostic messages written to standard
138 error.
139 NLSPATH Determine the location of message catalogs for the processing
141 of LC_MESSAGES.
142
144 Default.
145
147 When the −l option is used, the standard output shall contain all sup‐
148 ported fromcode and tocode values, written in an unspecified format.
149 When the −l option is not used, the standard output shall contain the
151 sequence of characters read from the input files, translated to the
152 specified codeset. Nothing else shall be written to the standard out‐
153 put.
154
156 The standard error shall be used only for diagnostic messages.
157
159 None.
160
162 None.
163
165 The following exit values shall be returned:
166 0 Successful completion.
168 >0 An error occurred.
170
172 Default.
173 The following sections are informative.
175
177 The user must ensure that both charmap files use the same symbolic
178 names for characters the two codesets have in common.
179
181 The following example converts the contents of file mail.x400 from the
182 ISO/IEC 6937:2001 standard codeset to the ISO/IEC 8859‐1:1998 standard
183 codeset, and stores the results in file mail.local:
184 iconv −f IS6937 −t IS8859 mail.x400 > mail.local
186
188 The iconv utility can be used portably only when the user provides two
189 charmap files as option-arguments. This is because a single charmap
190 provided by the user cannot reliably be joined with the names in a sys‐
191 tem-provided character set description. The valid values for fromcode
192 and tocode are implementation-defined and do not have to have any rela‐
193 tion to the charmap mechanisms. As an aid to interactive users, the −l
194 option was adopted from the Plan 9 operating system. It writes informa‐
195 tion concerning these implementation-defined values. The format is
196 unspecified because there are many possible useful formats that could
197 be chosen, such as a matrix of valid combinations of fromcode and
198 tocode. The −l option is not intended for shell script usage; conform‐
199 ing applications will have to use charmaps.
200 The iconv utility may support the conversion between ASCII and EBCDIC-
202 based encodings, but is not required to do so. In an XSI-compliant
203 implementation, the dd utility is the only method guaranteed to support
204 conversion between these two character sets.
205
207 None.
208
210 dd, gencat
211 The Base Definitions volume of POSIX.1‐2008, Section 6.4, Character Set
213 Description File, Chapter 8, Environment Variables, Section 12.2, Util‐
214 ity Syntax Guidelines
215
217 Portions of this text are reprinted and reproduced in electronic form
218 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
219 -- Portable Operating System Interface (POSIX), The Open Group Base
220 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
221 cal and Electronics Engineers, Inc and The Open Group. (This is
222 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
223 event of any discrepancy between this version and the original IEEE and
224 The Open Group Standard, the original IEEE and The Open Group Standard
225 is the referee document. The original Standard can be obtained online
226 at http://www.unix.org/online.html .
227 Any typographical or formatting errors that appear in this page are
229 most likely to have been introduced during the conversion of the source
230 files to man page format. To report such errors, see https://www.ker‐
231 nel.org/doc/man-pages/reporting_bugs.html .
232IEEE/The Open Group 2013 ICONV(1P)