bsfilt(1)

NAME

     bsfilt, colcrt - a colcrt-like backspace filter

SYNOPSIS

     bsfilt [ - ] [ -U ] [ file ... ]

DESCRIPTION

     Bsfilt filters backspace sequences from the input file(s) (standard input
     if  none)  in  an approximation of colcrt(1).  Both the backspace and the
     character it returns to  are  removed,  unless  they  form  an  underline
     sequence.   Underline  sequences are treated according to the settings of
     the - and -U options.

OPTIONS

     -    specifies that no underlining of  any  kind  is  to  be  propagated.
          Without   this   option   or  the  -U  option,  bsfilt  approximates
          underlining with minus signs (`-') in following lines.

     -U   specifies that underlining with underscore (`_') and backspace (`b')
          character sequences is permitted.

SEE ALSO

     cawf(1), colcrt(1) and nroff(1).

DIAGNOSTICS

     Diagnostic messages are delivered to the standard error file.

HISTORY

     Vic Abell of Purdue University wrote bsfilt to have  a  backspace  filter
     for cawf(1) that is independent of licensed source code.

BUGS

     The maximum length of a line that can be underlined with minus  signs  is
     fixed.

     Bsfilt does not examine the characters that  are  being  overprinted  via
     backspace  operations.  Thus, overprinting that is intended to form a new
     character from several different ones is ineffective and  only  the  last
     character  of  the  sequence is propagated - e. g., ``o^H+'', intended to
     look like a bullet, is reduced to `+'.