On 6/19/22 00:38, sur-behoffski wrote:
Yes, and this comes up even in strict POSIX without GNU extensions, as "a^" is a valid extended regular expression that cannot match anything.a\<b [abc]\>[def]
I don't know whether dfa.c, regex.c, etc. optimize for this, but if not it would be nice if they did. For example, 'grep -E "a^" FOO' can silently exit with status 1 without even opening FOO.
