This page discusses deletion of age-expired files from the /tmp directory in Enterprise Linux 6.
The default /tmp deletion job is /etc/cron.daily/tmpwatch which contains the following:
#! /bin/sh
flags=-umc
/usr/sbin/tmpwatch "$flags" -x /tmp/.X11-unix -x /tmp/.XIM-unix \
-x /tmp/.font-unix -x /tmp/.ICE-unix -x /tmp/.Test-unix \
-X '/tmp/hsperfdata_*' 10d /tmp
/usr/sbin/tmpwatch "$flags" 30d /var/tmp
for d in /var/{cache/man,catman}/{cat?,X11R6/cat?,local/cat?}; do
if [ -d "$d" ]; then
/usr/sbin/tmpwatch "$flags" -f 30d "$d"
fi
done
In the above script the first call to /usr/sbin/tmpwatch deletes all files from /tmp that are more than 10 days old, with the exception of files in directories specified by the -x (exclude) parameter.
Scripts in /etc/cron.daily are executed by anacron which executes commands periodically with a frequency specified in days. Unlike cron, anacron does not assume that the server is running continuously.
Anacron is configured in /etc/anacrontab. By default /etc/anacrontab contains the following:
[root@vm19 cron.daily]# cat /etc/anacrontab # /etc/anacrontab: configuration file for anacron # See anacron(8) and anacrontab(5) for details. SHELL=/bin/sh PATH=/sbin:/bin:/usr/sbin:/usr/bin MAILTO=root # the maximal random delay added to the base delay of the jobs RANDOM_DELAY=45 # the jobs will be started during the following hours only START_HOURS_RANGE=3-22 #period in days delay in minutes job-identifier command 1 5 cron.daily nice run-parts /etc/cron.daily 7 25 cron.weekly nice run-parts /etc/cron.weekly @monthly 45 cron.monthly nice run-parts /etc/cron.monthly
Anacron stores its timestamp files in /var/spool/anacron. There are three timestamps representing the last day, week and month that the respective scripts were executed:
[root@vm19]# cd /var/spool/anacron [root@vm19]# ls -l total 12 -rw-------. 1 root root 9 Jun 15 03:39 cron.daily -rw-------. 1 root root 9 May 23 12:15 cron.monthly -rw-------. 1 root root 9 Jun 14 10:48 cron.weekly [root@vm19]# cat cron.daily 20150615 [root@vm19]# cat cron.weekly 20150614 [root@vm19]# cat cron.monthly 20150523