If I use a long regular expression in Notepad++, i.e.:
^([^ ]+) ([^ ]+) ([^ ]+) (\[.*?\]) (".*?") (".*?") (".*?") (".*?") (\d+) (\d+) (\d+)$
(this is for turning an Apache log lines from space-separated to tab-separated)
then I can't successfully use more than nine backreferences for replacing, as \10 yields the content of the first captured group plus a literal "0".
I tried with $10, but that gives the same result.