[ILUG] col(1)-ish tool emulating destructive ^H ?

[kevin lyda]

On Mon, Feb 16, 2004 at 10:01:53PM +0100, Brian Foster wrote:
>   I ran into a small annoyance today and am wondering if
>  anyone has, or knows of, an existing fix/work-around
> 
>   the problem is `col -b' emulates non-destructive BS
>  (backspace), such as happens on hardcopy printers (e.g.,
>  DECwriters, lineprinters, teletypes, &tc).  namely,
>  the sequence (where SP means SP (space) and BS means BS;
>  for those not displaying UTF-8/Unicode correctly,
>  a transliteration is given on the right):
> 
>       x BS SP
> 
>  where <x> is any _printing_ character, is turned into
>  (by `col -b'):
> 
>       x

no it isn't.  it's turned into SP according to the man page:

    -b  Do not output any backspaces, printing only the last
        character written to each column position.

>  (this is quite possibly the only `col' transformation I
>  care about --- there is no reverse line motion or (known)

in general i'd do something like this in perl:

    #!/usr/bin/perl -n

    chomp;
    $i = 0;
    @l = ();
    foreach (split(//, $_)) {
        if ($_ eq '\b') {
            $i-- if ($i);
        } else {
            $l[$i++] = $_;
        }
    }
    print(join("", @l). "\n");

but again, that's what col -b is supposed to do.

kevin

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