${FILENAME} means the whole filename(entered in output filename field in replace dialog) ${BASE} means the filename without extension. ${EXT} means the extension, if file has no extesion, abc.${EXT} will equal to 'abc', not 'abc.' ${FIRSTLINE} means the using the firstline in the file as part or whole of the filename. # means sequence No. occupying 1 character space. ## means sequence No. occupying 2 character spaces. ... @ means sequence No. from 'a' to 'z' @@ means sequence No. from 'aa' to 'zz' @@@ and more means sequence No. from 'aaa' to 'zzz'
Advanced Rules: ${FILENAME}{n1,n2} means the character n1 to character n2 of the ${FILENAME}, if n1<0 or n2<0 means count from end.