NAME

       bidiv - bidirectional text filter

SYNOPSIS

       bidiv [ -plj ] [ -w width ] [file...]

DESCRIPTION

       bidiv  is  a  filter, or viewer, for birectional text stored in logical-order. It converts
       such text into visual-order text which can be viewed  on  terminals  that  do  not  handle
       bidirectionality.  The  output  visual-order  text is formatted assuming a fixed number of
       characters per line (automatically determined or given with the -w parameter).

       bidiv is oriented towards Hebrew, and assumes the input to be  a  Hebrew  and  ASCII  text
       encoded in one of the two common logical-order encodings: ISO-8859-8-i or UTF-8. Actually,
       bidiv guesses the encoding of its input at a character by character basis,  so  the  input
       might  be a mix of ISO-8859-8-i and Hebrew UTF-8.  bidiv's output is visual-order text, in
       either the ISO-8859-8 or UTF-8 encoding, depending on your locale setting.

       bidiv reads each file in sequence, converts it into visual order  and  writes  it  on  the
       standard output.  Thus:

              $ bidiv file

       prints   file   on   your  terminal  (assuming  it  has  the  appropriate  fonts,  but  no
       bidirectionality support), and:

              $ bidiv file1 file2 | less

       concatenates file1 and file2, and shows the results using the pager less.

       If no input file is given, bidiv reads from the standard input file.

       For more ideas on how to use bidiv, see the EXAMPLES section below.

OPTIONS

       -p     Paragraph-based direction (default): When formatting a bidirectional  output  line,
              bidiv  needs to be aware of that line's base direction. A line whose base direction
              is RTL (right to left) gets right-justified and its first element  appears  on  the
              right.  Otherwise,  the line is left-justified and its first element appears on the
              left.

              The -p option tells bidiv to  choose  a  base  direction  per  paragraph,  where  a
              paragraph  is  delimited  by  an  empty line. This is bidiv's default behavior, and
              usually gives the expected results on most texts and emails.

              The direction of the entire paragraph is chosen according to  the  first  strongly-
              directioned  character  (i.e., an alphabetic character) appearing in the paragraph.
              Currently, if the first output line of a paragraph has  no  directional  characters
              (e.g.,  a  line of minus signs before an email signature, or a line containing only
              numbers) that line is output with the same direction of the previous paragraph, but
              it does not determine the direction of the rest of the paragraph. If the first line
              of the first paragraph does not have a direction, the RTL direction is  arbitrarily
              chosen.

       -l     Line-based  direction:  This  option  choose an alternative method of choosing each
              output line's base direction. When this option is enabled, the  base  direction  of
              each  output line is determined on its own (again, according to the first character
              on the line with a strong direction). This method may give  wrong  results  in  the
              case  where a line starts with a word of the opposite direction. This case is rare,
              but does happen under random line-splitting circumstances,  or  when  the  text  is
              defining words of a foreign language.

       -j     Do  not  justify:  By default, RTL lines are right-justified, i.e., they are padded
              with spaces on the left when shorter than the  required  line  width  (see  the  -w
              option).  The  -j  option tells bidiv not to preform this justifications, and leave
              short lines unpadded.

       -w width
              bidiv formats its output for lines of the given width. Lines are split when  longer
              than  this width, and RTL lines are right-justfied to fill that width unless the -j
              option is given.

              When the -w option is not given, bidiv uses the  value  of  the  COLUMNS  variable,
              which  is usually automatically defined by the user's shell.  When that both the -w
              option and the COLUMNS variable are missing, the default of 80 columns is used.

OPERANDS

       The following operand is supported:

       file    A path name of an input file.  If no file is  specified,  the  standard  input  is
               used.

EXAMPLES

       1. bidiv README | less

       2. man something | bidiv | less

          (or groff -man -Tlatin1 something.1 |sed 's/.^H\(.\)/\1/g' |../bidiv -w 65)

       3. set  "bidiv" as a filter for your mail program (mutt, pine, etc.) for viewing mail with
          the ISO 8859-8-i character set, and Hebrew UTF-8 mail.

ENVIRONMENT

       COLUMNS see -w option.

EXIT STATUS

       The following exit values are returned:

       0   All input files were output successfully.

       >0  An error occurred.

AUTHOR

       Written by Nadav Har'El, http://nadav.harel.org.il.

       Please send bug reports and comments to nyh@math.technion.ac.il.

       The     latest     version     of     this     software     can      be      found      in
       ftp://ftp.ivrix.org.il/pub/ivrix/src/cmdline

SEE ALSO

       cat(1), fribidi(3)