You can run a one time command with the at command. The at command will run a command at a specified time in the future. As an example suppose April 4 at 11:00 PM you start downoloading a large number of files, through your 14.4 Kb modem. Your wife needs the phone at 6AM. So you run the following command.
at 06:00 apr 04 at pppoff at <EOT>(EOT = the control key then the d key or d)
To send yourself a reminder to not burn dinner in 15 minutes, use the next sequence.
at now + 15 minutes at echo "Dinner is burning" | mail yourusername at <EOT>You can use the 'now + # time-unit' to run a command from now until that amount of time. Where time-unit could be minutes, hours, days, or weeks. You can also use tomorrow or the British time frame "teatime". :=) See man at for more information.