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.\" 33.Dd October 21, 2020 34.Dt COL 1 35.Os 36.Sh NAME 37.Nm col 38.Nd filter reverse line feeds from input 39.Sh SYNOPSIS 40.Nm 41.Op Fl bfhpx 42.Op Fl l Ar num 43.Sh DESCRIPTION 44The 45.Nm 46utility filters out reverse (and half reverse) line feeds so that the output is 47in the correct order with only forward and half forward line 48feeds, and replaces white-space characters with tabs where possible. 49.Pp 50The 51.Nm 52utility reads from the standard input and writes to the standard output. 53.Pp 54The options are as follows: 55.Bl -tag -width indent 56.It Fl b 57Do not output any backspaces, printing only the last character 58written to each column position. 59.It Fl f 60Forward half line feeds are permitted (``fine'' mode). 61Normally characters printed on a half line boundary are printed 62on the following line. 63.It Fl h 64Do not output multiple spaces instead of tabs (default). 65.It Fl l Ar num 66Buffer at least 67.Ar num 68lines in memory. 69By default, 128 lines are buffered. 70.It Fl p 71Force unknown control sequences to be passed through unchanged. 72Normally, 73.Nm 74will filter out any control sequences from the input other than those 75recognized and interpreted by itself, which are listed below. 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 "carriage return" -compact 92.It ESC\-BELL 93reverse line feed (escape then bell). 94.It ESC\-7 95reverse line feed (escape then 7). 96.It ESC\-BACKSPACE 97half reverse line feed (escape then backspace). 98.It ESC\-8 99half reverse line feed (escape then 8). 100.It ESC\-TAB 101half forward line feed (escape than tab). 102.It ESC\-9 103half forward line feed (escape then 9). 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 128The 129.Nm 130utility keeps track of the character set as characters are read and makes 131sure the character set is correct when they are output. 132.Pp 133If the input attempts to back up to the last flushed line, 134.Nm 135will display a warning message. 136.Sh ENVIRONMENT 137The 138.Ev LANG , LC_ALL 139and 140.Ev LC_CTYPE 141environment variables affect the execution of 142.Nm 143as described in 144.Xr environ 7 . 145.Sh EXIT STATUS 146.Ex -std 147.Sh EXAMPLES 148We can use 149.Nm 150to filter the output of 151.Xr man 1 152and remove the backspace characters ( 153.Em ^H 154) before searching for some text: 155.Bd -literal -offset indent 156man ls | col -b | grep HISTORY 157.Ed 158.Sh SEE ALSO 159.Xr expand 1 160.Sh STANDARDS 161The 162.Nm 163utility conforms to 164.St -susv2 . 165.Sh HISTORY 166A 167.Nm 168command 169appeared in 170.At v6 . 171