1COL(1)                      General Commands Manual                     COL(1)
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NAME

6       col - filter reverse line feeds
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SYNOPSIS

9       col [-bfx]
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DESCRIPTION

12       Col  reads  the standard input and writes the standard output.  It per‐
13       forms the line overlays implied by reverse line feeds (ESC-7 in  ASCII)
14       and  by  forward and reverse half line feeds (ESC-9 and ESC-8).  Col is
15       particularly useful for filtering  multicolumn  output  made  with  the
16       `.rt' command of nroff and output resulting from use of the tbl(1) pre‐
17       processor.
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19       Although col accepts half line motions in its input, it  normally  does
20       not emit them on output.  Instead, text that would appear between lines
21       is moved to the next lower full line boundary.  This treatment  can  be
22       suppressed  by  the  -f (fine) option; in this case the output from col
23       may contain forward half line feeds (ESC-9), but will still never  con‐
24       tain either kind of reverse line motion.
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26       If the -b option is given, col assumes that the output device in use is
27       not capable of backspacing.  In this case, if several characters are to
28       appear in the same place, only the last one read will be taken.
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30       The control characters SO (ASCII code 017), and SI (016) are assumed to
31       start and end text in an alternate character set.   The  character  set
32       (primary  or alternate) associated with each printing character read is
33       remembered; on output, SO and SI characters are generated where  neces‐
34       sary to maintain the correct treatment of each character.
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36       Col normally converts white space to tabs to shorten printing time.  If
37       the -x option is given, this conversion is suppressed.
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39       All control  characters  are  removed  from  the  input  except  space,
40       backspace,  tab, return, newline, ESC (033) followed by one of 789, SI,
41       SO, and VT (013).  This last character is an  alternate  form  of  full
42       reverse  line  feed, for compatibility with some other hardware conven‐
43       tions.  All other non-printing characters are ignored.
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SEE ALSO

46       troff(1), tbl(1), greek(1)
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BUGS

49       Can't back up more than 128 lines.
50       No more than 800 characters, including backspaces, on a line.
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