ANACRONTAB(5)

NAME
/etc/anacrontab - monotonic jobs

DESCRIPTION
The file /etc/anacrontab follow the rules previously set by anacron(8).

Lines starting with '#' are comments.

Environment variables can be set using VAR=VALUE keypairs.

The special RANDOM_DELAY (in minutes) environment variable is translated to RandomizedDelaySec=. The special START_HOURS_RANGE (in hours) environment variable is translated to the 'hour' component of OnCalendar=. anacron expect a range in the format ##-##, systemd-crontab-generator only uses the starting hour of the range as reference. The other lines are job-descriptions that follow this layout:

period delay job-identifier command

*   period is a number of days to wait between each job execution, or special values @daily, @weekly, @monthly, @yearly

*   delay is a number of extra minutes to wait before starting job. It is translated in OnBootSec=

*   job-identifier is a single word. systemd-crontab-generator uses it to construct the dynamic unit names: cron-job-identifier-root-0.timer and matching cron-job-identifier-root-0.service

*   command is the command that is run by a shell

BUGS
systemd-crontab-generator doesn't support multiline commands.

Any period greater than 30 is rounded to the closest month

There are subtle differences on how anacron & systemd handle persistente timers: anacron will run a weekly job at most once a week, with always a minimum delay of 6 days between runs; where systemd will try to run it every monday at 00:00; or as soon the system boot. In the most extreme case, if a system was only started on sunday; a weekly job will run this day and the again the next (mon)day.
There is no difference for the daily job.

DIAGNOSTICS
After editing /etc/anacrontab, you can run journalctl -n and systemctl list-timers to see if the timers have well been updated.

SEE ALSO
systemd-crontab-generator(8), systemd.timer(5)

AUTHOR
Alexandre Detiste <alexandre.detiste@gmail.com>