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 (con-
       sult 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 standard 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 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
       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 posi-
              tions 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 Variables for the precedence  of  international-
              ization 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 stan-
              dard 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  access-
       ing 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 sorting, 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 integers (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,  Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                    EXPAND(1P)