# 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 `+'.