{} = the file "find" found
-e = that you wanna do a one-liner
-i = that you wanna run the one-liner on a file ({} in this case)
-p = can't explain this one in an understandable way
Taken from the man page....
causes Perl to assume the following loop around your script, which makes it iterate over filename arguments somewhat like sed.
Great that you got it to work