“The subject of this week’s column is how to manage your
appointments using a simple reminder service, the calendar
tool.“
“It reportedly first appeared in Version 7 of AT&T Unix, and
was rewritten early on for the BSD family of Unix. The BSD derivate
is available for Debian as part of the bsdmainutils package, but
this tool isn’t yet standard on all Linux distributions (including
Red Hat). If your distribution doesn’t have it, you can obtain the
source package from Debian.”
“When calendar executes, it reads a “calendar file” in the
current directory which contains a list of appointments and
reminders, and it outputs those entries in the file for today or
tomorrow’s date. (On a Friday, it outputs entries for that weekend
and for the following Monday.)”