Re: DEL character treated specially when preceded by a backslash when used in the RHS of the regex operator ([[ $'\177' =~ $'\\\177' ]])

[Chet Ramey]

On 1/17/14, 2:30 PM, Eduardo A. Bustamante López wrote:

> So, in short, there are three issues here:
> 
> 1) Why is $'\177' handled differently (just that non-graphic
> character, in comparison to the other non-graphic)?

I covered this earlier.

> 2) What's the reason of the incompatible behavior between bash in
> ubuntu vs bash in cygwin (i.e. the [[ keyword returning 2 for
> characters outside the ASCII range when trying to match them with =~)

Because the regexp engine refuses to compile it (regcomp() returns non-
zero).  Bash doesn't use its own regexp engine.

> 3) How should bash treat the case of a character preceded by a
> backslash in regular expressions (and globs, as Dan reported in a
> previous issue)?

I am getting to the point where I think that if a backslash makes it
through word expansion it should be quoted for the regexp engine.  Other
shells seem to agree on this point, though others are less clear.

Chet
-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/