Help for this page

Select Code to Download

Select or download this

$ perl -Mre=debug -E'qr/(a) \1 1/x'
Compiling REx "(a) \1 1"
...
  11: END (0)
anchored "a" at 0 floating "1" at 1..2147483647 (checking floating) mi
+nlen 2 
Freeing REx: "(a)(?:\1)1"