DragonFly On-Line Manual Pages
VIS(1) DragonFly General Commands Manual VIS(1)
NAME
vis -- display non-printable characters in a visual format
SYNOPSIS
vis [-abcfhlMmNnoSstw] [-e extra] [-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:
-a Encode all characters, whether originally visible or not.
(VIS_ALL)
-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 ``cat -v''. (VIS_NOSLASH)
-c Request a format which displays a small subset of the non-
printable characters using C-style backslash sequences.
(VIS_CSTYLE)
-e extra
Also encode characters in extra, per svis(3).
-F foldwidth
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 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 Same as -F.
-h Encode using the URI encoding from RFC 1808. (VIS_HTTPSTYLE)
-l Mark newlines with the visible sequence `\$', followed by the
newline.
-M Encode all shell meta characters (implies -S, -w, -g) (VIS_META)
-m Encode using the MIME Quoted-Printable encoding from RFC 2045.
(VIS_MIMESTYLE)
-N Turn on the VIS_NOLOCALE flag which encodes using the ``C''
locale, removing any encoding dependencies caused by the current
locale settings specified in the environment.
-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. (VIS_OCTAL)
-S Encode shell meta-characters that are non-white space or glob.
(VIS_SHELL)
-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. (VIS_SAFE)
-t Tabs are also encoded. (VIS_TAB)
-w White space (space-tab-newline) is also encoded. (VIS_WHITE)
MULTIBYTE CHARACTER SUPPORT
vis supports multibyte character input. The encoding conversion is
influenced by the setting of the LC_CTYPE environment variable which
defines the set of characters that can be copied without encoding.
When 8-bit data is present in the input, LC_CTYPE must be set to the
correct locale or to the C locale. If the locales of the data and the
conversion are mismatched, multibyte character recognition may fail and
encoding will be performed byte-by-byte instead.
ENVIRONMENT
LC_CTYPE Specify the locale of the input data. Set to C if the input
data locale is unknown.
SEE ALSO
unvis(1), svis(3), vis(3)
HISTORY
The vis command appeared in 4.4BSD. Multibyte character support was
added in NetBSD 7.0 and FreeBSD 9.2.
DragonFly 5.3 June 10, 2018 DragonFly 5.3