VIS(1) MachTen Reference Manual VIS(1)

NAME
vis - display non-printable characters in a visual format

SYNOPSIS
vis [-cbflnostw] [-F foldwidth] [file ...]

DESCRIPTION
Vis is a filter for converting non-printable characters into a visual
representation. It differs from ‘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 vis(3).

The options are as follows:

-b Turns off prepending of backslash before up-arrow control se-
quences and meta characters, and disables the doubling of back-
slashes. This produces output which is neither invertible or
precise, but does represent a minimum of change to the input. It
is similar to ‘‘cat -v’’.

-c Request a format which displays a small subset of the non-
printable characters using C-style backslash sequences.

-F Causes vis to fold output lines to foldwidth columns (default
80), like fold(1), except that a hidden newline sequence is
used, (which is removed when inverting the file back to its orig-
inal form with unvis(1)). If the last character in the encoded
file does not end in a newline, a hidden newline sequence is ap-
pended to the output. This makes the output usable with various
editors and other utilities which typically don’t work with par-
tial lines.

-f Same as -F.

-l Mark newlines with the visible sequence ‘, followed by the
newline.

-n Turns off any encoding, except for the fact that backslashes are
still doubled and hidden newline sequences inserted if -f or -F
is selected. When combined with the -f flag, vis becomes like an
invertible version of the fold(1) utility. That is, the output
can be unfolded by running the output through

-o Request a format which displays non-printable characters as an
octal number, dd.

-s Only characters considered unsafe to send to a terminal are en-
coded. This flag allows backspace, bell, and carriage return in
addition to the default space, tab and newline. unvis(1).

-t Tabs are also encoded.

-w White space (space-tab-newline) is also encoded.