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 October 21, 2020 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. 50.Pp 51The 52.Nm 53utility reads from the standard input and writes to the standard output. 54.Pp 55The options are as follows: 56.Bl -tag -width indent 57.It Fl b 58Do not output any backspaces, printing only the last character 59written to each column position. 60.It Fl f 61Forward half line feeds are permitted (``fine'' mode). 62Normally characters printed on a half line boundary are printed 63on the following line. 64.It Fl h 65Do not output multiple spaces instead of tabs (default). 66.It Fl l Ar num 67Buffer at least 68.Ar num 69lines in memory. 70By default, 128 lines are buffered. 71.It Fl p 72Force unknown control sequences to be passed through unchanged. 73Normally, 74.Nm 75will filter out any control sequences from the input other than those 76recognized and interpreted by itself, which are listed below. 77.It Fl x 78Output multiple spaces instead of tabs. 79.El 80.Pp 81In the input stream, 82.Nm 83understands both the escape sequences of the form escape-digit 84mandated by 85.St -susv2 86and the traditional 87.Bx 88format escape-control-character. 89The control sequences for carriage motion and their ASCII values 90are as follows: 91.Pp 92.Bl -tag -width "carriage return" -compact 93.It ESC\-BELL 94reverse line feed (escape then bell). 95.It ESC\-7 96reverse line feed (escape then 7). 97.It ESC\-BACKSPACE 98half reverse line feed (escape then backspace). 99.It ESC\-8 100half reverse line feed (escape then 8). 101.It ESC\-TAB 102half forward line feed (escape than tab). 103.It ESC\-9 104half forward line feed (escape then 9). 105In 106.Fl f 107mode, this sequence may also occur in the output stream. 108.It backspace 109moves back one column (8); ignored in the first column 110.It carriage return 111(13) 112.It newline 113forward line feed (10); also does carriage return 114.It shift in 115shift to normal character set (15) 116.It shift out 117shift to alternate character set (14) 118.It space 119moves forward one column (32) 120.It tab 121moves forward to next tab stop (9) 122.It vertical tab 123reverse line feed (11) 124.El 125.Pp 126All unrecognized control characters and escape sequences are 127discarded. 128.Pp 129The 130.Nm 131utility keeps track of the character set as characters are read and makes 132sure the character set is correct when they are output. 133.Pp 134If the input attempts to back up to the last flushed line, 135.Nm 136will display a warning message. 137.Sh ENVIRONMENT 138The 139.Ev LANG , LC_ALL 140and 141.Ev LC_CTYPE 142environment variables affect the execution of 143.Nm 144as described in 145.Xr environ 7 . 146.Sh EXIT STATUS 147.Ex -std 148.Sh EXAMPLES 149We can use 150.Nm 151to filter the output of 152.Xr man 1 153and remove the backspace characters ( 154.Em ^H 155) before searching for some text: 156.Bd -literal -offset indent 157man ls | col -b | grep HISTORY 158.Ed 159.Sh SEE ALSO 160.Xr expand 1 161.Sh STANDARDS 162The 163.Nm 164utility conforms to 165.St -susv2 . 166.Sh HISTORY 167A 168.Nm 169command 170appeared in 171.At v6 . 172