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VIS(1) General Commands Manual VIS(1) NAME vis -- display non-printable characters in a visual format SYNOPSIS vis [-bcfhlMmNnoSstw] [-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: -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". (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 en- coded 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" lo- cale, 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 en- coded. 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 in- fluenced by the setting of the LC_CTYPE environment variable which de- fines 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. EXAMPLES Visualize characters encoding white spaces and tabs: $ echo -e "\x10\n\t" | vis -w -t \^P\012\011\012 Same as above but using `\$' for newline followed by an actual newline: $ echo -e "\x10\n\t" | vis -w -t -l \^P\$ \011\$ Visualize string using URI encoding: $ echo http://www.freebsd.org | vis -h http%3a%2f%2fwww.freebsd.org%0a SEE ALSO unvis(1), svis(3), vis(3) HISTORY The vis command appears in 4.4BSD. Multibyte character support was added in NetBSD 7.0 and FreeBSD 9.2. FreeBSD 13.2 February 18, 2021 VIS(1)
NAME | SYNOPSIS | DESCRIPTION | MULTIBYTE CHARACTER SUPPORT | ENVIRONMENT | EXAMPLES | SEE ALSO | HISTORY
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