use Modern::Perl; for ( grep /\S/, ) { my @data = ( split /\./ )[ 0 .. 3 ]; splice @data, 1, 1, unpack '(a4)(a2)*', $data[1]; say "@data"; } __DATA__ 3B40RT.2000033121.7.bin.gz 3B40RT.2000033121.7R.bin.gz 3B40RT.2000033121.7RWER.bin.gz