(recode.info)ASCII-BS

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ASCII 7-bits, `BS' to overstrike
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   This charset is available in `recode' under the name `ASCII-BS',
with `BS' as an acceptable alias.

   The file is straight ASCII, seven bits only.  According to the
definition of ASCII, diacritics are applied by a sequence of three
characters: the letter, one `BS', the diacritic mark.  We deviate
slightly from this by exchanging the diacritic mark and the letter so,
on a screen device, the diacritic will disappear and let the letter
alone.  At recognition time, both methods are acceptable.

   The French quotes are coded by the sequences: `< BS "' or `" BS <'
for the opening quote and `> BS "' or `" BS >' for the closing quote.
This artificial convention was inherited in straight `ASCII-BS' from
habits around `Bang-Bang' entry, and is not well known.  But we decided
to stick to it so that `ASCII-BS' charset will not lose French quotes.

   The `ASCII-BS' charset is independent of `ASCII', and different.
The following examples demonstrate this, knowing at advance that `!2'
is the `Bang-Bang' way of representing an `e' with an acute accent.
Compare:

     % echo \!2 | recode -v bang..l1/d
     Request: Bang-Bang..ISO-8859-1/Decimal-1
     233,  10

with:

     % echo \!2 | recode -v bang..bs/d
     Request: Bang-Bang..ISO-8859-1..ASCII-BS/Decimal-1
      39,   8, 101,  10

   In the first case, the `e' with an acute accent is merely
transmitted by the `Latin-1..ASCII' mapping, not having a special
recoding rule for it.  In the `Latin-1..ASCII-BS' case, the acute
accent is applied over the `e' with a backspace: diacriticised
characters have special rules.  For the `ASCII-BS' charset,
reversibility is still possible, but there might be difficult cases.