Ubuntu Manpage: bidiv - bidirectional text filter

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