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 .

IEEE/The Open Group                                   2003                                             EXPAND(P)