.TH COL 1.SH NAMEcol \- filter reverse line feeds.SH SYNOPSIS.B col [\|\-bfx\|].SH DESCRIPTION.I Colreads the standard input and writes the standard output.It performs the line overlays implied by reverse linefeeds (ESC-7 in ASCII)and by forward and reverse half line feeds (ESC-9 and ESC-8)..I Colis particularly useful for filtering multicolumnoutput made with the `.rt' command of.I nroffand output resulting from use of the.IR tbl (1)preprocessor..PPAlthough.I colaccepts half line motions in its input, it normally does notemit them on output.Instead, text that would appear between lines is moved to the next lowerfull line boundary.This treatment can be suppressed by the.B \-f(fine) option; in this casethe output from.I colmay contain forward half line feeds (ESC-9), but will still never containeither kind of reverse line motion..PPIf the.B \-boption is given,.I colassumes 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..PPThe control characters SO (ASCII code 017),and SI (016) are assumedto start and end text in an alternate character set.The character set (primary or alternate) associated with each printingcharacter read is remembered; on output, SO and SI characters are generatedwhere necessary to maintain the correct treatment of each character..PP.I Colnormally converts white space to tabs to shorten printing time.If the.B \-xoption is given, this conversion is suppressed..PPAll control characters are removed from the input except space,backspace,tab, return, newline, ESC (033) followed by one of 789, SI, SO, and VT(013).This last character is an alternate form of full reverse line feed, forcompatibility with some other hardware conventions.All other non-printing characters are ignored..SH "SEE ALSO"troff(1), tbl(1), greek(1).SH BUGSCan't back up more than 128 lines..brNo more than 800 characters, including backspaces, on a line.