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

PROLOG
       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
       expand - convert tabs to spaces
SYNOPSIS
       expand [-t tablist][file ...]
DESCRIPTION
       The expand utility shall write files or the standard input to the stan-
       dard  output  with  <tab>s replaced with one or more <space>s needed to
       pad to the next tab stop. Any <backspace>s shall be copied to the  out-
       put and cause the column position count for tab stop calculations to be
       decremented; the column position count shall not be  decremented  below
       zero.
OPTIONS
       The  expand  utility  shall  conform  to the Base Definitions volume of
       IEEE Std 1003.1-2001, 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>s or commas, in ascending order. The tabs  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
       The following operand shall be supported:
       file   The pathname of a text file to be used as input.

STDIN
       See the INPUT FILES section.
INPUT FILES
       Input files shall be text files.
ENVIRONMENT VARIABLES
       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
              IEEE Std 1003.1-2001, Section  8.2,  Internationalization  Vari-
              ables  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>s and <space>s, 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
       Default.
STDOUT
       The standard output shall be equivalent to the input files with  <tab>s
       converted into the appropriate number of <space>s.
STDERR
       The standard error shall be used only for diagnostic messages.
OUTPUT FILES
       None.
EXTENDED DESCRIPTION
       None.
EXIT STATUS
       The following exit values shall be returned:
        0     Successful completion
       >0     An error occurred.

CONSEQUENCES OF ERRORS
       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
       None.
EXAMPLES
       None.
RATIONALE
       The expand utility is useful for preprocessing text files (before sort-
       ing, looking at specific columns, and so on) that contain <tab>s.
       See the Base Definitions volume of IEEE Std 1003.1-2001, 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  inte-
       gers  (within  the  single  argument)  separated using either commas or
       <blank>s.
FUTURE DIRECTIONS
       None.
SEE ALSO
       tabs, unexpand
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 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 .

IEEE/The Open Group                  2003                           EXPAND(1P)