1.\" Copyright (c) 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Michael Rendell. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)col.1 8.1 (Berkeley) 6/29/93 32.\" $FreeBSD$ 33.\" 34.Dd May 10, 2015 35.Dt COL 1 36.Os 37.Sh NAME 38.Nm col 39.Nd filter reverse line feeds from input 40.Sh SYNOPSIS 41.Nm 42.Op Fl bfhpx 43.Op Fl l Ar num 44.Sh DESCRIPTION 45The 46.Nm 47utility filters out reverse (and half reverse) line feeds so that the output is 48in the correct order with only forward and half forward line 49feeds, and replaces white-space characters with tabs where possible. 50This can be useful in processing the output of 51.Xr nroff 1 52and 53.Xr tbl 1 . 54.Pp 55The 56.Nm 57utility reads from the standard input and writes to the standard output. 58.Pp 59The options are as follows: 60.Bl -tag -width indent 61.It Fl b 62Do not output any backspaces, printing only the last character 63written to each column position. 64.It Fl f 65Forward half line feeds are permitted (``fine'' mode). 66Normally characters printed on a half line boundary are printed 67on the following line. 68.It Fl h 69Do not output multiple spaces instead of tabs (default). 70.It Fl l Ar num 71Buffer at least 72.Ar num 73lines in memory. 74By default, 128 lines are buffered. 75.It Fl p 76Force unknown control sequences to be passed through unchanged. 77Normally, 78.Nm 79will filter out any control sequences from the input other than those 80recognized and interpreted by itself, which are listed below. 81.It Fl x 82Output multiple spaces instead of tabs. 83.El 84.Pp 85In the input stream, 86.Nm 87understands both the escape sequences of the form escape-digit 88mandated by 89.St -susv2 90and the traditional 91.Bx 92format escape-control-character. 93The control sequences for carriage motion and their ASCII values 94are as follows: 95.Pp 96.Bl -tag -width "carriage return" -compact 97.It ESC\-BELL 98reverse line feed (escape then bell). 99.It ESC\-7 100reverse line feed (escape then 7). 101.It ESC\-BACKSPACE 102half reverse line feed (escape then backspace). 103.It ESC\-8 104half reverse line feed (escape then 8). 105.It ESC\-TAB 106half forward line feed (escape than tab). 107.It ESC\-9 108half forward line feed (escape then 9). 109In 110.Fl f 111mode, this sequence may also occur in the output stream. 112.It backspace 113moves back one column (8); ignored in the first column 114.It carriage return 115(13) 116.It newline 117forward line feed (10); also does carriage return 118.It shift in 119shift to normal character set (15) 120.It shift out 121shift to alternate character set (14) 122.It space 123moves forward one column (32) 124.It tab 125moves forward to next tab stop (9) 126.It vertical tab 127reverse line feed (11) 128.El 129.Pp 130All unrecognized control characters and escape sequences are 131discarded. 132.Pp 133The 134.Nm 135utility keeps track of the character set as characters are read and makes 136sure the character set is correct when they are output. 137.Pp 138If the input attempts to back up to the last flushed line, 139.Nm 140will display a warning message. 141.Sh ENVIRONMENT 142The 143.Ev LANG , LC_ALL 144and 145.Ev LC_CTYPE 146environment variables affect the execution of 147.Nm 148as described in 149.Xr environ 7 . 150.Sh EXIT STATUS 151.Ex -std 152.Sh SEE ALSO 153.Xr colcrt 1 , 154.Xr expand 1 , 155.Xr nroff 1 , 156.Xr tbl 1 157.Sh STANDARDS 158The 159.Nm 160utility conforms to 161.St -susv2 . 162.Sh HISTORY 163A 164.Nm 165command 166appeared in 167.At v6 . 168