unexpand(1)							   unexpand(1)

NAME    [Toc]    [Back]

     unexpand -	convert	spaces to tabs

SYNOPSIS    [Toc]    [Back]

     unexpand [	-a| -t tablist ] [ file..]

DESCRIPTION    [Toc]    [Back]

     The unexpand utility copies files or the standard input to	the standard
     output, converting	blank characters at the	beginning of each line into
     the maximum number	of tab characters followed by the minimum number of
     space characters needed to	fill the same column positions originally
     filled by the translated blank characters.	By default, tabstops are set
     at	every eighth column position. Each backspace character is copied to
     the output, and causes the	column position	count for tab calculations to
     be	decremented; the count will never be decremented to a value less than
     one.

OPTIONS    [Toc]    [Back]

     The following options are supported:

     -a	  In addition to translating blank characters at the beginning of each
	  line,	translate all sequences	of two or more blank characters
	  immediately preceding	a tab stop to the maximum number of tab
	  characters followed by the minimum number of space characters	needed
	  to fill the same column positions originally filled by the
	  translated blank characters.

     -t	tablist
	  Specify the tab stops. The option-argument tablist must be a single
	  argument consisting  of a single positive decimal integer or
	  multiple positive decimal integers, separated	by blank characters or
	  commas, in ascending order. If a single number is given, tabs	will
	  be set tablist column	positions apart	instead	of the default 8.  If
	  multiple numbers are given, the tabs will be set at those specific
	  column positions.

	  Each tab-stop	position N must	be an integer value greater than zero,
	  and the list must be in strictly ascending order. This is taken to
	  mean that, from the start of a line of output, tabbing to position N
	  causes the next character output to be in the	(N+1)th	column
	  position on that line. When the -t option is not specified, the
	  default is the equivalent of specifying -t 8 (except for the
	  interaction with -a, described below).

	  No space-to-tab character conversions	occur for characters at
	  positions beyond the last of those specified in a multiple tab-stop
	  list.

	  When -t is specified,	the presence or	absence	of the -a option is
	  ignored; conversion will not be limited to the processing of leading
	  blank	characters.




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unexpand(1)							   unexpand(1)

OPERANDS    [Toc]    [Back]

     The following operand is supported:

     -t	file   The pathname of a text file to be used as input.

STDIN    [Toc]    [Back]

     See INPUT FILES.

INPUT FILES    [Toc]    [Back]

     Input files must be text files.

ENVIRONMENT VARIABLES    [Toc]    [Back]

     The following environment variables affect	the execution of unexpand:

     LANG      Provide a default value for the internationalisation variables
     that are unset or null. If	LANG is	unset or null, the corresponding value
     from the implementation-specific default locale will be used. If any of
     the internationalisation variables	contains an invalid setting, the
     utility will behave as if none of the variables had been defined.

     LC_ALL	 If set	to a non-empty string value, override the values of
     all the other internationalisation	variables.

     LC_CTYPE	   Determine the locale	for the	interpretation of sequences of
     bytes of text data	as characters (for example, single- as opposed to
     multi-byte	characters in arguments	and input files), the processing of
     tab and space characters, and for the determination of the	width in
     column positions each character would occupy on a constant-width font
     output device.

     LC_MESSAGES      Determine	the locale that	should be used to affect the
     format and	contents of diagnostic messages	written	to standard error.

ASYNCHRONOUS EVENTS    [Toc]    [Back]

     Default.

STDOUT    [Toc]    [Back]

     The standard output is equivalent to the input files with the specified
     space to tab character conversions.

STDERR    [Toc]    [Back]

     Used only for diagnostic messages.

OUTPUT FILES    [Toc]    [Back]

     None.






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unexpand(1)							   unexpand(1)

EXTENDED DESCRIPTION    [Toc]    [Back]

     None.

EXIT STATUS    [Toc]    [Back]

     The following exit	values are returned:

     0 Successful completion.

     >0	An error occurred.


CONSEQUENCES OF	ERRORS
     Default.

APPLICATION USAGE    [Toc]    [Back]

     One non-intuitive aspect of unexpand is its restriction to	leading	spaces
     when neither -a nor -t is specified. Users	who desire to always convert
     all spaces	in a file can easily alias unexpand to use the -a or -t	8
     option.

EXAMPLES    [Toc]    [Back]

     None.

FUTURE DIRECTIONS    [Toc]    [Back]

     None.

SEE ALSO    [Toc]    [Back]

     tabs, expand

CHANGE HISTORY    [Toc]    [Back]

     First released in Issue 4.


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