We started this chapter by showing the new at
command and explaining how we can use at
for scheduling scripts. We described the timestamp syntax for at
and how it contains a queue for all scheduled jobs. We explained how at
is mostly used for ad hoc scheduled commands and scripts, before we continued to the more powerful cron
scheduler.
The cron
daemon, responsible for most scheduled tasks on a system, is a very powerful and flexible scheduler, which is most often used via the so-called crontab. This is a user-bound file, which contains instructions for cron
on when and how to run commands and scripts. We presented the timestamp syntax that is used in a crontab.
The second part of the chapter dealt with logging our scheduled commands and scripts. When a command is run interactively on the command line, there is no need for dedicated logging, but scheduled commands are not interactive, and thus need additional mechanisms. Output from scheduled commands can either be mailed to a local...