1.\" $OpenBSD: col.1,v 1.15 2020/02/08 01:09:57 jsg Exp $ 2.\" $NetBSD: col.1,v 1.4 1995/03/26 05:25:52 glass Exp $ 3.\" 4.\" Copyright (c) 1990, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" Michael Rendell. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)col.1 8.1 (Berkeley) 6/29/93 35.\" 36.Dd $Mdocdate: February 8 2020 $ 37.Dt COL 1 38.Os 39.Sh NAME 40.Nm col 41.Nd filter reverse line feeds and backspaces from input 42.Sh SYNOPSIS 43.Nm col 44.Op Fl bfhx 45.Op Fl l Ar num 46.Sh DESCRIPTION 47.Nm 48filters out reverse (and half-reverse) line feeds so that the output is 49in the correct order with only forward and half-forward line 50feeds, and replaces whitespace characters with tabs where possible. 51.Pp 52.Nm 53reads from the standard input and writes to the standard output. 54.Pp 55The options are as follows: 56.Bl -tag -width Ds 57.It Fl b 58Do not output any backspaces, printing only the last character 59written to each column position. 60This can be useful in processing the output of 61.Xr mandoc 1 . 62.It Fl f 63Forward half-line feeds are permitted 64.Pf ( Dq fine 65mode). 66Normally characters printed on a half-line boundary are printed 67on the following line. 68.It Fl h 69Compress spaces into tabs. 70This is the default behavior. 71.It Fl l Ar num 72Buffer at least 73.Ar num 74lines in memory. 75By default, 128 lines are buffered. 76.It Fl x 77Output multiple spaces instead of tabs. 78.El 79.Pp 80In the input stream, 81.Nm 82understands both the escape sequences of the form escape-digit 83mandated by 84.St -susv2 85and the traditional 86.Bx 87format escape-control-character. 88The control sequences for carriage motion and their ASCII values 89are as follows: 90.Pp 91.Bl -tag -width "escape-backspace" -compact 92.It escape\-bell 93Reverse line feed (27 then 7). 94.It escape\-digit\-7 95Reverse line feed (27 then 55). 96.It escape\-backspace 97Half reverse line feed (27 then 8). 98.It escape\-digit\-8 99Half reverse line feed (27 then 56). 100.It escape\-tab 101Half forward line feed (27 then 9). 102.It escape\-digit\-9 103Half forward line feed (27 then 57). 104In 105.Fl f 106mode, this sequence may also occur in the output stream. 107.It backspace 108Moves back one column (8); ignored in the first column. 109.It carriage return 110(13) 111.It newline 112Forward line feed (10); also does carriage return. 113.It shift in 114Shift to normal character set (15). 115.It shift out 116Shift to alternate character set (14). 117.It space 118Moves forward one column (32). 119.It tab 120Moves forward to next tab stop (9). 121.It vertical tab 122Reverse line feed (11). 123.El 124.Pp 125All unrecognized control characters and escape sequences are 126discarded. 127.Pp 128.Nm 129keeps track of the character set as characters are read and makes 130sure the character set is correct when they are output. 131.Pp 132If the input attempts to back up to the last flushed line, 133.Nm 134will display a warning message. 135.Sh SEE ALSO 136.Xr expand 1 137.Sh HISTORY 138A 139.Nm 140command appeared in 141.At v5 . 142