I can't really understand how anacron works on my laptop. How can anacron wake up and start every morning, when I don't turn off my laptop?
I've setup a backup process, taking advantage of backup2l. Apparently, when I don't shutdown my laptop, backup2l starts every morning at 7:30 am, I suppose thanks to anacron: > $ ls -l /etc/cron.daily/zz-backup2l > -rwxr-xr-x 1 root root 328 Jan 4 2005 /etc/cron.daily/zz-backup2l > $ cat /etc/anacrontab > # /etc/anacrontab: configuration file for anacron > > # See anacron(8) and anacrontab(5) for details. > > SHELL=/bin/sh > PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin > HOME=/root > LOGNAME=root > > # These replace cron's entries > 1 5 cron.daily run-parts --report /etc/cron.daily > 7 10 cron.weekly run-parts --report /etc/cron.weekly > @monthly 15 cron.monthly run-parts --report > /etc/cron.monthly But what triggers anacron? Looking at my crontab, it would seem it's not cron that starts anacron: > $ cat /etc/crontab > # /etc/crontab: system-wide crontab > # Unlike any other crontab you don't have to run the `crontab' > # command to install the new version when you edit this file > # and files in /etc/cron.d. These files also have username fields, > # that none of the other crontabs do. > > SHELL=/bin/sh > PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin > > # m h dom mon dow user command > 17 * * * * root cd / && run-parts --report /etc/cron.hourly > 25 6 * * * root test -x /usr/sbin/anacron || ( cd / && > run-parts --report /etc/cron.daily ) > 47 6 * * 7 root test -x /usr/sbin/anacron || ( cd / && > run-parts --report /etc/cron.weekly ) > 52 6 1 * * root test -x /usr/sbin/anacron || ( cd / && > run-parts --report /etc/cron.monthly ) > # Here's what I've found in my syslog: > $ sudo grep cron /var/log/syslog > Jul 12 06:25:01 aldous CRON[10672]: (root) CMD (test -x > /usr/sbin/anacron || ( cd / && run-parts --report /etc/cron.daily )) This depends on my /etc/crontab. As expected, nothing happens here. > Jul 12 07:05:30 aldous anacron[9445]: Job `cron.daily' terminated > (mailing output) > Jul 12 07:05:30 aldous anacron[9445]: Can't find sendmail at > /usr/sbin/sendmail, not mailing output > Jul 12 07:05:30 aldous anacron[9445]: Normal exit (1 job run) > Jul 12 07:05:30 aldous anacron[9445]: anacron: Can't find sendmail at > /usr/sbin/sendmail, not mailing output But now... what triggered anacron at 07:05:30? > Jul 12 07:17:01 aldous CRON[11658]: (root) CMD ( cd / && run-parts > --report /etc/cron.hourly) > Jul 12 07:30:01 aldous CRON[11716]: (root) CMD (test -x > /etc/init.d/anacron && /usr/sbin/invoke-rc.d anacron start >/dev/null) > Jul 12 07:30:01 aldous anacron[11736]: Anacron 2.3 started on 2016-07-12 > Jul 12 07:30:01 aldous anacron[11736]: Normal exit (0 jobs run) This time it seems it's cron that triggers anacron. But why, considering my /etc/crontab shown above? What other configuration files does cron take into account? Besides, why anacron says "0 jobs run", when at least one job (zz-backup2l) is in fact run? I'm rather confused!
