4.4.1. Use that idle time!
A Linux system can have a lot to suffer from, but it usually
suffers only during office hours. Whether in an office environment,
a server room or at home, most Linux systems are just idling away
during the morning, the evening, the nights and weekends. Using
this idle time can be a lot cheaper than buying those machines
you'd absolutely need if you want everything done at the same
There are three types of delayed execution:
Waiting a little while and then resuming job execution, using
the sleep command. Execution time depends on
the system time at the moment of submission.
Running a command at a specified time, using the at command. Execution of the job(s) depends on system
time, not the time of submission.
Regularly running a command on a monthly, weekly, daily or
hourly basis, using the cron facilities.
The following sections discuss each possibility.