Files listed on the command line are read as input, unless there are none, in which case standard input is used. The input files should have been generated by nroff. The output goes to outfile if the -o option is used, otherwise to standard output.
The count given with the -s option requires a bit of
explanation.
Suppose we want to output
,
This is best handled as a single unit, i.e.,
foo, bar^H^H^H^H^H^H^H^H___ ___
If the spacing is greater, e.g.,
,
it's probably faster to backspace separately for each word, i.e.,
foo^H^H^H___, bar^H^H^H___
Count is the maximum number of consecutive non-overstruck characters that
can be between two groups of overstruck characters and still have the
backspacing for both groups be done at once.
The default for count is 4.
The backspacing for the characters that precede a control character or escape sequence is always done separately from the backspacing for the characters that follow. The control character or escape sequence itself is always output verbatim, and is not involved in backspace processing. An escape sequence is always assumed to consist of ESC followed by one character. The characters SO (ASCII \016) and SI (ASCII \017) are assumed to begin and end a sequence of characters from an alternate character set. They and the characters they delimit are output verbatim without any processing of imbedded backspaces. Roffix recognizes the following control characters and escape sequences for the purpose of keeping track of the current line number: new line, return, form feed, ESC 7 (reverse line feed), ESC 8 (reverse half line feed), ESC 9 (forward half line feed), and VT (ASCII \013 - interpreted as reverse line feed for compatibility with old programs).
Warnings are issued if there is any backspacing over a tab, new line, return, or form feed. Backspacing over other control characters is done without warnings; it is assumed nroff knows what it's doing.
The return value of roffix is the number of errors encountered (0 if no errors).