expand(P)                                             expand(P)





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 posi-
       tive decimal integers, separated by <blank>s or  commas,
       in  ascending order. The tabs shall be set at those spe-
       cific 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  multi-
       ple tab-stop list, the <tab> shall be replaced by a sin-
       gle <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, International-
              ization Variables for the precedence of  interna-
              tionalization  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 posi-
              tions 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 mes-
              sages 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

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in
       electronic form from  IEEE  Std  1003.1,  2003  Edition,
       Standard  for Information Technology -- Portable Operat-
       ing System Interface (POSIX), The Open Group Base Speci-
       fications Issue 6, Copyright (C) 2001-2003 by the Insti-
       tute 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 .



POSIX                         2003                    expand(P)
