weird oneline - who can explain it to me?

[Kim Schulz]

hi
a friend of mine just gave me this: 
perl -e 's$$7=78)1~61\@A6*:\@?~$*y+A~@%-?B+\-" a-z*+/s^^$_^ee'

can anyone explain it to me? 
I know that it deletes all files and folders not starting with a dot
(.), but how does it do it?

best regards
Kim S