答案1
你必须查看操作系统(ubuntu)内部,然后深入研究一下调用的内容。例如,每天cron
都会调用一堆系统调用和你在机器上运行的一些其他软件,所以我建议去那里看看
你可以看看ls -a /etc/cron.daily
,我有这个:
root@drvo:/# ll /etc/cron.daily/
total 60K
drwxr-xr-x 2 root root 4.0K Feb 15 12:46 ./
drwxr-xr-x 120 root root 12K Feb 15 12:43 ../
-rwxr-xr-x 1 root root 376 Jun 2 2020 apport*
-rwxr-xr-x 1 root root 1.5K Aug 11 2020 apt-compat*
-rwxr-xr-x 1 root root 1.1K Jun 27 2020 dpkg*
-rwxr-xr-x 1 root root 377 Sep 10 18:15 logrotate*
-rwxr-xr-x 1 root root 1.1K Jul 5 2020 man-db*
-rwxr-xr-x 1 root root 1.4K Apr 2 2020 ntp*
-rw-r--r-- 1 root root 102 Feb 13 2020 .placeholder
-rwxr-xr-x 1 root root 349 Apr 9 2019 quota*
-rwxr-xr-x 1 root root 1007 Feb 23 2020 rkhunter*
-rwxr-xr-x 1 root root 286 Aug 11 2020 roundcube-core*
-rwxr-xr-x 1 root root 1.5K Oct 15 2018 webalizer*