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

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 .