vis.1 (2010 09)

v
vis(1) vis(1)
NAME
vis, inv - make unprintable and non-ASCII characters in a file visible or invisible
SYNOPSIS
vis [-n][-s][
-t][-u][-x] file ...
inv [-n][-s][
-t][-u][-x] file ...
DESCRIPTION
vis 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 print-
able 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
\b backspace
\e escape
\f form-feed
\n new-line
\r carriage return
\s space
\t horizontal tab
\v vertical tab
\n the character whose ASCII code is the 3-digit octal number n.
\xn 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:
\n the 8-bit character whose code value is the 3-digit octal number n.
\xn 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 unal-
tered 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, vis and inv read from the standard input.
Options
vis and inv recognize the following options:
-n Treat new-line, space, and horizontal tab as non-printable characters.
vis expands them
visibly as
\n, \s, and \t, rather than passing them directly to the output.
inv discards
these characters, expecting only the printable expansions. New-line characters are
inserted by
vis every 16 bytes so that the output will be in a form that is usable by most
editors.
-s Make vis and inv 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.
-t Treat horizontal-tab and space characters as non-printable in the same manner that
-n
treats them.
-u Cause output to be unbuffered (byte-by-byte); normally, output is buffered.
-x Cause vis output to be in hexadecimal form rather than the default octal form. Either
form is accepted to inv as input.
EXTERNAL INFLUENCES
Environment Variables
LANG determines the language in which messages are displayed.
International Code Set Support
Single- and multi-byte character code sets are supported.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1