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

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

       expand — convert tabs to spaces

SYNOPSIS         top

       expand [−t tablist] [file...]

DESCRIPTION         top

       The expand utility shall write files or the standard input to the
       standard output with <tab> characters replaced with one or more
       <space> characters needed to pad to the next tab stop. Any
       <backspace> characters shall be copied to the output and cause the
       column position count for tab stop calculations to be decremented;
       the column position count shall not be decremented below zero.

OPTIONS         top

       The expand utility shall conform to the Base Definitions volume of
       POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       −t tablist
                 Specify the tab stops. The application shall ensure that
                 the argument tablist consists of either a single positive
                 decimal integer or a list of tabstops. If a single number
                 is given, tabs shall be set that number of column positions
                 apart instead of the default 8.

                 If a list of tabstops is given, the application shall
                 ensure that it consists of a list of two or more positive
                 decimal integers, separated by <blank> or <comma>
                 characters, in ascending order. The <tab> characters shall
                 be set at those specific column positions. Each tab stop N
                 shall be an integer value greater than zero, and the list
                 is in strictly ascending order. This is taken to mean that,
                 from the start of a line of output, tabbing to position N
                 shall cause the next character output to be in the (N+1)th
                 column position on that line.

                 In the event of expand having to process a <tab> at a
                 position beyond the last of those specified in a multiple
                 tab-stop list, the <tab> shall be replaced by a single
                 <space> in the output.

OPERANDS         top

       The following operand shall be supported:

       file      The pathname of a text file to be used as input.

STDIN         top

       See the INPUT FILES section.

INPUT FILES         top

       Input files shall be text files.

ENVIRONMENT VARIABLES         top

       The following environment variables shall affect the execution of
       expand:

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base Definitions
                 volume of POSIX.1‐2008, 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 and input
                 files), the processing of <tab> and <space> characters, and
                 for the determination of the width in column positions each
                 character would occupy on an output device.

       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

       The standard output shall be equivalent to the input files with <tab>
       characters converted into the appropriate number of <space>
       characters.

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

       The expand utility shall terminate with an error message and non-zero
       exit status upon encountering difficulties accessing one of the file
       operands.

       The following sections are informative.

APPLICATION USAGE         top

       None.

EXAMPLES         top

       None.

RATIONALE         top

       The expand utility is useful for preprocessing text files (before
       sorting, looking at specific columns, and so on) that contain <tab>
       characters.

       See the Base Definitions volume of POSIX.1‐2008, Section 3.103,
       Column Position.

       The tablist option-argument consists of integers in ascending order.
       Utility Syntax Guideline 8 mandates that expand shall accept the
       integers (within the single argument) separated using either <comma>
       or <blank> characters.

       Earlier versions of this standard allowed the following form in the
       SYNOPSIS:

           expand [−tabstop][−tab1,tab2,...,tabn][file ...]

       This form is no longer specified by POSIX.1‐2008 but may be present
       in some implementations.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       tabs(1p), unexpand(1p)

       The Base Definitions volume of POSIX.1‐2008, Section 3.103, Column
       Position, 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, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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                 2013                          EXPAND(1P)

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