Ordinarily, the mode line of the diary buffer window will indicate any
holidays that fall on the date of the diary entries. The process of
checking for holidays takes several seconds, so the display of the diary
buffer is delayed slightly because the holiday information is included.
If you'd prefer to have a faster display of the diary buffer but without
the holiday information, set the variable holidays-in-diary-buffer
to nil.
The variable number-of-diary-entries controls the number of days of
diary entries that will be displayed initially (when
view-diary-entries-initially is set to t) or with the
command M-x diary. For example, if the default value 1 is used,
then only the current day's diary entries will be displayed. If the
value 2 is used, both the current day's and the next day's entries will
be displayed. The value can also be a vector of seven elements: if the
value is [0 2 2 2 2 4 1] then no diary entries will be displayed
on Sunday, the current date's and the next day's diary entries will be
displayed Monday through Thursday, Friday through Monday's entries will
be displayed on Friday, while on Saturday only that day's entries will
be displayed.
The variable print-diary-entries-hook is the list of functions
called after a temporary buffer is prepared with the diary entries
currently visible in the diary buffer. The default value of this hook adds
a heading (composed from the diary buffer's mode line), does the printing
with the command lpr-buffer, and kills the temporary buffer. If you
want to use a different command to do the printing, just change the value
of this hook. Other uses might include, for example, rearranging the lines
into order by day and time.
You can customize the form of dates in your diary file if neither the standard American nor European styles suits your needs; to find out how, use C-h v diary-date-forms RET after entering the calendar. You can similarly customize the form in which dates are displayed in the diary, in mode lines, and in messages; use C-h v calendar-date-display-form RET after entering the calendar.