1EXPAND(1P) POSIX Programmer's Manual EXPAND(1P)
2
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.
10
12 expand — convert tabs to spaces
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15 expand [-t tablist] [file...]
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18 The expand utility shall write files or the standard input to the stan‐
19 dard output with <tab> characters replaced with one or more <space>
20 characters needed to pad to the next tab stop. Any <backspace> charac‐
21 ters shall be copied to the output and cause the column position count
22 for tab stop calculations to be decremented; the column position count
23 shall not be decremented below zero.
24
26 The expand utility shall conform to the Base Definitions volume of
27 POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
28 The following option shall be supported:
30 -t tablist
32 Specify the tab stops. The application shall ensure that the
33 argument tablist consists of either a single positive decimal
34 integer or a list of tabstops. If a single number is given,
35 tabs shall be set that number of column positions apart
36 instead of the default 8.
37 If a list of tabstops is given, the application shall ensure
39 that it consists of a list of two or more positive decimal
40 integers, separated by <blank> or <comma> characters, in
41 ascending order. The <tab> characters shall be set at those
42 specific column positions. Each tab stop N shall be an inte‐
43 ger value greater than zero, and the list is in strictly
44 ascending order. This is taken to mean that, from the start
45 of a line of output, tabbing to position N shall cause the
46 next character output to be in the (N+1)th column position on
47 that line.
48 In the event of expand having to process a <tab> at a posi‐
50 tion beyond the last of those specified in a multiple tab-
51 stop list, the <tab> shall be replaced by a single <space> in
52 the output.
53
55 The following operand shall be supported:
56 file The pathname of a text file to be used as input.
58
60 See the INPUT FILES section.
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63 Input files shall be text files.
64
66 The following environment variables shall affect the execution of
67 expand:
68 LANG Provide a default value for the internationalization vari‐
70 ables that are unset or null. (See the Base Definitions vol‐
71 ume of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
72 ables for the precedence of internationalization variables
73 used to determine the values of locale categories.)
74 LC_ALL If set to a non-empty string value, override the values of
76 all the other internationalization variables.
77 LC_CTYPE Determine the locale for the interpretation of sequences of
79 bytes of text data as characters (for example, single-byte as
80 opposed to multi-byte characters in arguments and input
81 files), the processing of <tab> and <space> characters, and
82 for the determination of the width in column positions each
83 character would occupy on an output device.
84 LC_MESSAGES
86 Determine the locale that should be used to affect the format
87 and contents of diagnostic messages written to standard
88 error.
89 NLSPATH Determine the location of message catalogs for the processing
91 of LC_MESSAGES.
92
94 Default.
95
97 The standard output shall be equivalent to the input files with <tab>
98 characters converted into the appropriate number of <space> characters.
99
101 The standard error shall be used only for diagnostic messages.
102
104 None.
105
107 None.
108
110 The following exit values shall be returned:
111 0 Successful completion
113 >0 An error occurred.
115
117 The expand utility shall terminate with an error message and non-zero
118 exit status upon encountering difficulties accessing one of the file
119 operands.
120 The following sections are informative.
122
124 None.
125
127 None.
128
130 The expand utility is useful for preprocessing text files (before sort‐
131 ing, looking at specific columns, and so on) that contain <tab> charac‐
132 ters.
133 See the Base Definitions volume of POSIX.1‐2017, Section 3.103, Column
135 Position.
136 The tablist option-argument consists of integers in ascending order.
138 Utility Syntax Guideline 8 mandates that expand shall accept the inte‐
139 gers (within the single argument) separated using either <comma> or
140 <blank> characters.
141 Earlier versions of this standard allowed the following form in the
143 SYNOPSIS:
144 expand [-tabstop][-tab1,tab2,...,tabn][file ...]
147 This form is no longer specified by POSIX.1‐2008 but may be present in
149 some implementations.
150
152 None.
153
155 tabs, unexpand
156 The Base Definitions volume of POSIX.1‐2017, Section 3.103, Column
158 Position, Chapter 8, Environment Variables, Section 12.2, Utility Syn‐
159 tax Guidelines
160
162 Portions of this text are reprinted and reproduced in electronic form
163 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
164 table Operating System Interface (POSIX), The Open Group Base Specifi‐
165 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
166 Electrical and Electronics Engineers, Inc and The Open Group. In the
167 event of any discrepancy between this version and the original IEEE and
168 The Open Group Standard, the original IEEE and The Open Group Standard
169 is the referee document. The original Standard can be obtained online
170 at http://www.opengroup.org/unix/online.html .
171 Any typographical or formatting errors that appear in this page are
173 most likely to have been introduced during the conversion of the source
174 files to man page format. To report such errors, see https://www.ker‐
175 nel.org/doc/man-pages/reporting_bugs.html .
176IEEE/The Open Group 2017 EXPAND(1P)