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col(1)			    General Commands Manual			col(1)

NAME
       col - filter reverse line-feeds and backspaces

SYNOPSIS
DESCRIPTION
       reads  from the standard	input and writes onto the standard output.  It
       performs	the line overlays implied by reverse line  feeds  (ASCII  code
       and  by	forward	and reverse half-line feeds and	is particularly	useful
       for filtering multi-column output made with the command,	and output re-
       sulting from use	of the preprocessor (see nroff(1) and tbl(1)).

       If  the	option	is given, assumes that the output device in use	is not
       capable of backspacing.	In this	case, if two or	more characters	are to
       appear in the same place, only the last one read	is output.

       If  the	option	is  given, assumes the output device is	a line printer
       (rather than a character	printer) and removes backspaces	 in  favor  of
       multiply	 overstruck  full  lines.   It generates the minimum number of
       print operations	necessary to generate the  required  number  of	 over-
       strikes.	  (All but the last print operation on a line are separated by
       carriage	returns	(\r); the last print operation is terminated by	a new-
       line (\n).)

       Although	 accepts  half-line motions in its input, it normally does not
       emit them on output.  Instead, text that	would appear between lines  is
       moved to	the next lower full-line boundary.  This treatment can be sup-
       pressed by the (fine) option; in	this case, the output from may contain
       forward	half-line  feeds  (ESC-9), but will still never	contain	either
       kind of reverse line motion.

       Unless the option is given, converts white  space  to  tabs  on	output
       wherever	possible to shorten printing time.

       The  ASCII control characters SO	(\016) and SI (\017) are assumed by to
       start and end text in an	alternate character set.  The character	set to
       which  each input character belongs is remembered, and on output	SI and
       SO characters are generated as appropriate to ensure that each  charac-
       ter is printed in the correct character set.

       On  input,  the	only control characters	accepted are space, backspace,
       tab, return, new-line, SI , SO ,	and VT , (\013), and ESC  followed  by
       or The VT character is an alternate form	of full	reverse	line-feed, in-
       cluded for compatibility	with some earlier programs of this type.   All
       other non-printing characters are ignored.

       Normally, ignores any unrecognized escape sequences found in its	input;
       the option can be used to cause to output these	sequences  as  regular
       characters, subject to overprinting from	reverse	line motions.  The use
       of this option is highly	discouraged unless the user is fully aware  of
       the textual position of the escape sequences.

EXTERNAL INFLUENCES
   Environment Variables
       provides	 a  default  value for the internationalization	variables that
       are unset or null. If is	unset or null, the default value of  "C"  (see
       lang(5))	is used. If any	of the internationalization variables contains
       an invalid setting, will	behave as if  all  internationalization	 vari-
       ables are set to	"C".  See environ(5).

       If  set	to  a  non-empty string	value, overrides the values of all the
       other internationalization variables.

       determines the interpretation of	text as	single and/or multi-byte char-
       acters,	the classification of characters as printable, and the charac-
       ters matched by character class expressions in regular expressions.

       determines the locale that should be used to affect the format and con-
       tents  of diagnostic messages written to	standard error and informative
       messages	written	to standard output.

       determines the location of message catalogues for the processing	of

   International Code Set Support
       Single- and multi-byte character	code sets are supported.

EXAMPLES
       is used most often with and A common usage is:

       (very similar to	the usual man(1) command).  This command allows	verti-
       cal  bars  and  outer  boxes to be printed for tables.  The file	is run
       through the preprocessor, and the output	is then	piped through  format-
       ting  the  output using the macros.  The	formatted output is then piped
       through which sets up the vertical bars and aligns the columns  in  the
       file.   The file	is finally piped through the command, which prints the
       output to the screen with underlining and highlighting substituted  for
       italic  and  bold  typefaces.  The option deletes excess	space from the
       output so that multiple blank lines are not printed to the screen.

SEE ALSO
       nroff(1), tbl(1), ul(1),	man(5).

NOTES
       The input format	accepted by matches the	output produced	by with	either
       the  or options.	 Use (and the option of	if the ultimate	disposition of
       the output of is	a device that can  interpret  half-line	 motions,  and
       otherwise.

BUGS
       Cannot  back up more than 128 lines.  Cannot back up across page	bound-
       aries.

       There is	a maximum  limit  for  the  number  of	characters,  including
       backspaces  and	overstrikes, on	a line.	 The maximum limit is at least
       800 characters.

       Local vertical motions that would result	in backing up over  the	 first
       line of the document are	ignored.  As a result, the first line must not
       have any	superscripts.

WARNINGS
       This command is likely to be withdrawn from X/Open standards.  Applica-
       tions  using  this command might	not be portable	to other vendors' sys-
       tems.

STANDARDS CONFORMANCE
									col(1)

NAME | SYNOPSIS | DESCRIPTION | EXTERNAL INFLUENCES | EXAMPLES | SEE ALSO | NOTES | BUGS | WARNINGS | STANDARDS CONFORMANCE

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