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@(#)vis.1 8.4 (Berkeley) 4/19/94
.Dd April 19, 1994 .Dt VIS 1 .Os .Sh NAME .Nm vis .Nd display non-printable characters in a visual format .Sh SYNOPSIS .Nm .Op Fl cbflnostw .Op Fl F Ar foldwidth .Op Ar file ... .Sh DESCRIPTION .Nm is a filter for converting non-printable characters into a visual representation. It differs from .Ql cat -v in that the form is unique and invertible. By default, all non-graphic characters except space, tab, and newline are encoded. A detailed description of the various visual formats is given in .Xr vis 3 .
p The options are as follows: l -tag -width Ds t Fl b Turns off prepending of backslash before up-arrow control sequences and meta characters, and disables the doubling of backslashes. This produces output which is neither invertible or precise, but does represent a minimum of change to the input. It is similar to .Dq Li cat -v . t Fl c Request a format which displays a small subset of the non-printable characters using C-style backslash sequences. t Fl F Causes .Nm to fold output lines to foldwidth columns (default 80), like .Xr fold 1 , except that a hidden newline sequence is used, (which is removed when inverting the file back to its original form with .Xr unvis 1 ) . If the last character in the encoded file does not end in a newline, a hidden newline sequence is appended to the output. This makes the output usable with various editors and other utilities which typically don't work with partial lines. t Fl f Same as .Fl F . t Fl l Mark newlines with the visible sequence .Ql \e$ , followed by the newline. t Fl n Turns off any encoding, except for the fact that backslashes are still doubled and hidden newline sequences inserted if .Fl f or .Fl F is selected. When combined with the .Fl f flag, .Nm becomes like an invertible version of the .Xr fold 1 utility. That is, the output can be unfolded by running the output through .Xr unvis 1 . t Fl o Request a format which displays non-printable characters as an octal number, \eddd. t Fl s Only characters considered unsafe to send to a terminal are encoded. This flag allows backspace, bell, and carriage return in addition to the default space, tab and newline. t Fl t Tabs are also encoded. t Fl w White space (space-tab-newline) is also encoded. .El .Sh SEE ALSO .Xr unvis 1 , .Xr vis 3 .Sh HISTORY The .Nm command appears in x 4.4 .
Indexes created Mon Oct 27 17:09:47 GMT 2025