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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 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  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>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 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


       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 .