calendar - reminder service
calendar [-] [-r]
- Work for every user and send mail to him
-r Restrict multiple execution on the same day
calendar # Check calendar file in current directory
calendar # Normary used under the control of cron(8)
calendar -r # Normary used in /etc/rc file
Basically calendar program consults the file calendar in the current
directory and display lines which contain today's or tomorrow's date.
Month-day formats such as '12/25', 'Dec. 25', 'december 25', '*/25',
'12/*', '*/*' are recognized. The asterisk means 'all' days or 'all'
months. On weekends 'tomorrow' extends through next Monday without any
consideration about holidays. To prevent ambiguity, the formats '25
Dec.' and '25/12' are not recognized.
When an argument - is present, calendar works for all users with a file
calendar in their login directories and sends them mail. Normally this
is done daily under the control of cron.
The -r option does its the same job as - option, but touches the calendar
to prevents further access on the same day. Normally this is done in the
/etc/rc file on a machine which may be booted several times in one day.