Renaming with script method regex calculation within filename string
i m looking for guidance on problem renaming files
i have got hundreds of filenames look like
aa-95865-00-bb.ext
aa-45732-00-bb.ext
aa-85855-00-bb.ext
aa-75263-00-bb.ext
aa-35165-00-bb.ext
i want to rename by replacing "00" with sum of five digits starting at index 4
eg "00" in the first filename to be replaced by 9+5+8+6+5 = 33, to be renamed as, aa-95865-33-bb.ext
"00" in the second filename to be replaced by 4+5+7+3+2 = 21, to be renamed as, aa-45732-21-bb.ext
and so on ..
please guide .. thanks ..