On 12/7/2013 3:33 PM, Peter Cordes wrote:
I agree your complaint seems valid, but it's the behaviour of the regex engine built into GNU libc (in this case). Bash on other platforms would use the regex engine in their system libc. (Unless I'm mistaken in my assumption that bash doesn't have its own regex engine.)
---- Maybe Bash could follow the example of GNU grep and add the defacto perl standard as listed here: http://en.wikipedia.org/wiki/Regular_expression There, it lists the simple and extended posix, and the third standard being perl's RE: "The Perl standard is still evolving in Perl 6, but the current set of symbols and syntax has become a de facto standard. Largely because of its expressive power, many other utilities and programming languages have adopted syntax similar to Perl's — for example, Java, JavaScript, Python, Ruby, Microsoft's .NET Framework, and the W3C's XML Schema all use regular expression syntax similar to Perl's. Some languages and tools such as Boost and PHP support multiple regular expression flavors. Perl-derivative regular expression implementations are not identical and usually implement a subset of features found in Perl 5.0, released in 1994. Perl sometimes does incorporate features initially found in other languages, for example, Perl 5.10 implements syntactic extensions originally developed in PCRE and Python An option: shopt -s regex=(basic|[extended]|pcre) where 'extended' is the default would be a great extension. Likely bash could just copy the re-engine selection and use-code from grep... Certainly wouldn't violate posix to have such an option.
