8.4.1 Formatting Basics

Each `%' element will be replaced by some string or other when the buffer in question is generated. `%5y' means "insert the `y' spec, and pad with spaces to get a 5-character field".

As with normal C and Emacs Lisp formatting strings, the numerical modifier between the `%' and the formatting type character will pad the output so that it is always at least that long. `%5y' will make the field always (at least) five characters wide by padding with spaces to the left. If you say `%-5y', it will pad to the right instead.

You may also wish to limit the length of the field to protect against particularly wide values. For that you can say `%4,6y', which means that the field will never be more than 6 characters wide and never less than 4 characters wide.

Also Gnus supports some extended format specifications, such as `%&user-date;'.