or download this
C:\Projekte>perl -Mre=Debug,ALL -e "shift=~/abcdefghijklmnopqrstuvwxyz
+X/" abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdef
ghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzXabcdefghijklmnopqrstuvw
+xyzabcdefghijklmnopqrstuvwxyz
...
Starting position does not contradict /^/m...
Guessed: match at offset 78
Freeing REx: "abcdefghijklmnopqrstuvwxyzX"