Actually I came to the conclusion that within [ ] (character set) a single \ should suffice:
Code:
$ [[ 'wibble\' =~ [\.]$ ]] && echo yes
yes
Certain bash versions (for example 3.2.25) have a bug here.
To also support them one can use \\ because
a buggy shell sees a \ and an okay shell sees two \ that is effectively the same as one \
The
[*{\.}]$ matches any string that ends with
* or
{ or
\ or
. or
}.
