vis(1) [mojave man page]

VIS(1)							    BSD General Commands Manual 						    VIS(1)

NAME

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

SYNOPSIS

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

DESCRIPTION

     The vis utility 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 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''.

     -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 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 do not work with partial 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 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 addi-
	     tion to the default space, tab and newline.

     -t      Tabs are also encoded.

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

SEE ALSO

     unvis(1), vis(3)

HISTORY

     The vis command appeared in 4.4BSD.

BUGS

     Due to limitations in the underlying vis(3) function, the vis utility does not recognize multibyte characters, and thus may consider them to
     be non-printable when they are in fact printable (and vice versa).

BSD
								   June 25, 2004							       BSD

vis(1)							      General Commands Manual							    vis(1)

NAME

       vis, inv - make unprintable and non-ASCII characters in a file visible or invisible

SYNOPSIS

       file ...

       file ...

DESCRIPTION

       reads  characters  from	each file in sequence and writes them to the standard output, converting those that are not printable or not ASCII
       into a visible form.  inv performs the inverse function, reading printable characters from each file, returning them  to  non-printable	or
       non-ASCII form, if appropriate, then writing them to standard output;

       Non-printable ASCII characters are represented using C-like escape conventions:
	      backslash
	      backspace
	      escape
	      form-feed
	      new-line
	      carriage return
	      space
	      horizontal tab
	      vertical tab
	      the character whose
		      ASCII code is the 3-digit octal number n.
	      the character whose
		      ASCII code is the 2-digit hexadecimal number n.

       Non-ASCII  single-  or multi-byte characters are examined one byte at a time.  For each byte, if it can be displayed as an ASCII character,
       it is treated as if it is an ASCII character; Otherwise, it is represented in the following conventions:
	      the 8-bit character whose
		      code value is the 3-digit octal number n.
	      the 8-bit character whose
		      code value is the 2-digit hexadecimal number n.

       Space, horizontal-tab, and new-line characters can be treated as printable (and therefore passed unaltered to the output) or  non-printable
       depending  on  the  options  selected.	Backslash,  although printable, is expanded by vis, to a pair of backslashes so that when they are
       passed back through inv, they convert back to a single backslash.

       If no input file is given, or if the argument is encountered, and inv read from the standard input.

   Options
       and recognize the following options:

	      Treat new-line, space, and horizontal tab as non-printable characters.
		      expands them visibly as and rather than passing them directly to the output.  discards these characters, expecting only  the
		      printable  expansions.   New-line  characters  are  inserted  by every 16 bytes so that the output will be in a form that is
		      usable by most editors.

	      Make    and silent about non-existent files, identical input and output, and write errors.  Normally, no input file can be the  same
		      as the output file unless it is a special file.

	      Treat horizontal-tab and space characters as non-printable
		      in the same manner that treats them.

	      Cause output to be unbuffered (byte-by-byte);
		      normally, output is buffered.

	      Cause   output to be in hexadecimal form rather than the default octal form.  Either form is accepted to as input.

EXTERNAL INFLUENCES

   Environment Variables
       determines the language in which messages are displayed.

   International Code Set Support
       Single- and multi-byte character code sets are supported.

WARNINGS

       Redirecting output to an input file destroys the original data.	Therefore, command forms such as

       should be avoided unless the source file can be safely discarded.

AUTHOR

       was developed by HP.

SEE ALSO

       cat(1), echo(1), od(1).

																	    vis(1)