reversing a list Post: 29833

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LEARN ABOUT BSD

col

COL(1)							      General Commands Manual							    COL(1)

NAME

       col - filter reverse line feeds

SYNOPSIS

       col [ -bfh ]

DESCRIPTION

       Col  reads the standard input and writes the standard output.  It performs the line overlays implied by reverse line feeds (ESC-7 in ASCII)
       and by forward and reverse half line feeds (ESC-9 and ESC-8).  Col is particularly useful for filtering multicolumn output  made  with  the
       `.rt' command of nroff and output resulting from use of the tbl(1) preprocessor.

       Although  col  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 suppressed by the -f (fine) option; in  this  case  the  output
       from col may contain forward half line feeds (ESC-9), but will still never contain either kind of reverse line motion.

       If  the	-b  option is given, col assumes that the output device in use is not capable of backspacing.  In this case, if several characters
       are to appear in the same place, only the last one read will be taken.

       The control characters SO (ASCII code 017), and SI (016) are assumed to start and end text in an alternate character  set.   The  character
       set  (primary or alternate) associated with each printing character read is remembered; on output, SO and SI characters are generated where
       necessary to maintain the correct treatment of each character.

       If the -h option is given, col converts white space to tabs to shorten printing time.

       All control characters are removed from the input except space, backspace, tab, return, newline, ESC (033) followed by one of 7, 8, 9,  SI,
       SO,  and  VT (013).  This last character is an alternate form of full reverse line feed, for compatibility with some other hardware conven-
       tions.  All other non-printing characters are ignored.

SEE ALSO

       troff(1), tbl(1)

BUGS

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

7th Edition							   May 16, 1986 							    COL(1)