Managing time-triggered events with Zeit
Timetable
© Photo by Matthew Smith on Unsplash
Zeit offers a graphic front end for the crontab and at tools, making it easier to manage the time-controlled execution of programs, alarms, and timers.
When it comes to managing the time-controlled execution of programs, you can use the entries in the /etc/crontab file (crontab) for repetitive tasks scheduled at regular intervals, or you can use the at command for a one-time action.
While at uses a kind of order book that stores the commands to be executed at a scheduled time, cron works somewhat differently. The crontab contains the entries for the whole system, while the files in /var/spool/cron/crontabs/ contain user-specific entries. Each line in the crontab fully describes a single job. Care must be taken when specifying the jobs because of the entry format's fairly arcane syntax. You can learn this syntax, but it is by no means a trivial task. If you have an LPIC-1 certificate, you will be familiar with the entry format.
Despite care and attention, you may find out that jobs fail to start or are executed at the wrong time. A graphical user interface (GUI) can help reduce errors, even for experienced users. However, several earlier attempts at a suitable GUI for time-controlled calls (e.g., KCron, Kcrontab, CroMagnon, Gnome Schedule [1], Gnome Task Scheduler [2], and VCron) have fallen short with development coming to a standstill.
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