Should be fixed now. Please try. > CL-USER> (cl-ppcre:regex-replace-all (cl-ppcre:create-scanner "^$" :multi-line-mode t) *str* "!") It's shorter to write (cl-ppcre:regex-replace-all "(?m)^$" *str* "!") instead. This will also allow the compiler macro to compile the regex at load time. Cheers, Edi.