VIS(1)                     OpenBSD Reference Manual                     VIS(1)

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



SYNOPSIS
     vis [-cbflnostw] [-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 nor
             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-print-
             able 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 orig-
             inal form with unvis(1)).  If the last character in the encoded
             file does not end in a newline, a hidden newline sequence is ap-
             pended to the output.  This makes the output usable with various
             editors and other utilities which typically don't work with par-
             tial 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 en-
             coded.  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.

SEE ALSO
     unvis(1),  vis(3)

HISTORY
     The vis command appeared in 4.4BSD.

OpenBSD 2.6                     April 19, 1994                               1