bsfilt, colcrt - a colcrt-like backspace filter
bsfilt [ - ] [ -U ] [ file ... ]
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.
- 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.
cawf(1), colcrt(1) and nroff(1).
Diagnostic messages are delivered to the standard error file.
Vic Abell of Purdue University wrote bsfilt to have a backspace filter
for cawf(1) that is independent of licensed source code.
The maximum length of a line that can be underlined with minus signs is
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 `+'.