VIS(1) OpenBSD Reference Manual VIS(1)NAMEvis - display non-printable characters in a visual format
SYNOPSISvis [-abcflnostw] [-F foldwidth] [file ...]
DESCRIPTIONvis is a filter for converting non-printable characters into a visual
representation. It differs from cat -v in that the form can be unique
and invertible. By default, all non-printing characters except space,
tab, and newline are encoded, as are any meta-characters (eighth bit
set). A detailed description of the various visual formats is given in
vis(3).
The options are as follows:
-a Encode all characters, whether originally visible or not.
-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
nor 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 foldwidth
Causes vis to fold output lines to foldwidth columns, like
fold(1), except that a hidden newline sequence is used, (which is
removed when inverting the file back to its original form with
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.
-f Like -F, except output is always folded to 80 columns.
-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 unvis(1).
-o Request a format which displays non-printable characters as an
octal number, \ddd.
-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. Meta-
characters that are considered graphic characters by isgraph(3)
are not encoded.
-t Tabs are also encoded.
-w White space (space-tab-newline) is also encoded.
SEE ALSOunvis(1), vis(3)HISTORY
The vis command appeared in 4.4BSD.
OpenBSD 4.9 August 24, 2010 OpenBSD 4.9
