vis -- display non-printable characters in a visual format
vis [-cbflnostw] [-F foldwidth] [file ...]
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 don't work with partial
-f Same as -F.
-l Mark newlines with the visible sequence `\$', followed by the
-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.
-t Tabs are also encoded.
-w White space (space-tab-newline) is also encoded.
The vis command appeared in 4.4BSD.
FreeBSD 5.2.1 April 19, 1994 FreeBSD 5.2.1 [ Back ]