1.\" $NetBSD: vis.1,v 1.9 2002/09/30 11:09:16 grant Exp $ 2.\" 3.\" Copyright (c) 1989, 1991, 1993, 1994 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. 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.\" @(#)vis.1 8.4 (Berkeley) 4/19/94 35.\" 36.Dd April 19, 1994 37.Dt VIS 1 38.Os 39.Sh NAME 40.Nm vis 41.Nd display non-printable characters in a visual format 42.Sh SYNOPSIS 43.Nm 44.Op Fl cbflnostw 45.Op Fl F Ar foldwidth 46.Op Ar file ... 47.Sh DESCRIPTION 48.Nm 49is a filter for converting non-printable characters 50into a visual representation. 51It differs from 52.Ql cat -v 53in that 54the form is unique and invertible. 55By default, all non-graphic 56characters except space, tab, and newline are encoded. 57A detailed description of the 58various visual formats is given in 59.Xr vis 3 . 60.Pp 61The options are as follows: 62.Bl -tag -width Ds 63.It Fl b 64Turns off prepending of backslash before up-arrow control sequences 65and meta characters, and disables the doubling of backslashes. 66This 67produces output which is neither invertible or precise, but does 68represent a minimum of change to the input. 69It is similar to 70.Dq Li cat -v . 71.It Fl c 72Request a format which displays a small subset of the 73non-printable characters using C-style backslash sequences. 74.It Fl F 75Causes 76.Nm 77to fold output lines to foldwidth columns (default 80), like 78.Xr fold 1 , 79except 80that a hidden newline sequence is used, (which is removed 81when inverting the file back to its original form with 82.Xr unvis 1 ) . 83If the last character in the encoded file does not end in a newline, 84a hidden newline sequence is appended to the output. 85This makes 86the output usable with various editors and other utilities which 87typically don't work with partial lines. 88.It Fl f 89Same as 90.Fl F . 91.It Fl l 92Mark newlines with the visible sequence 93.Ql \e$ , 94followed by the newline. 95.It Fl n 96Turns off any encoding, except for the fact that backslashes are 97still doubled and hidden newline sequences inserted if 98.Fl f 99or 100.Fl F 101is selected. 102When combined with the 103.Fl f 104flag, 105.Nm 106becomes like 107an invertible version of the 108.Xr fold 1 109utility. 110That is, the output can be unfolded by running the output through 111.Xr unvis 1 . 112.It Fl o 113Request a format which displays non-printable characters as 114an octal number, \eddd. 115.It Fl s 116Only characters considered unsafe to send to a terminal are encoded. 117This flag allows backspace, bell, and carriage return in addition 118to the default space, tab and newline. 119.It Fl t 120Tabs are also encoded. 121.It Fl w 122White space (space-tab-newline) is also encoded. 123.El 124.Sh SEE ALSO 125.Xr unvis 1 , 126.Xr vis 3 127.Sh HISTORY 128The 129.Nm 130command appears in 131.Bx 4.4 . 132