expand(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

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.1‐2017, 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.1‐2017, 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 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.1‐2017, 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.1‐2017, 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 1003.1-2017, 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                        EXPAND(1P)

Pages that refer to this page: pr(1p)tabs(1p)unexpand(1p)