In the last pargraph of "Recursive grep" findstr command line was described as:
An alternative if you have a recent version of grep is to customize
‘grep-find-command’ to use ‘grep -r’ instead of both find and grep.
Another alternative if you don’t need the full capabilities of grep is
to use ‘findstr /n /r’.
The correct command line should be "findstr /n /r /s" the /r option enables regexp, /s option means recursive into sub-directory.
Thanks,
Kai