How is the /tmp directory cleaned up?

Question

How is the /tmp directory cleaned up? Is it automatic? If so, how frequently is it cleaned up?

Answer 1

The directory is cleared by default at every boot, because TMPTIME is 0 by default.

Here you can change the time in the following file:

/etc/default/rcS

TMPTIME says how frequent the tmp dir sould be cleared in days

Answer 2

While the /tmp folder is not a place to store files long-term, occasionally you want to keep things a little longer than the next time you reboot, which is the default on Ubuntu systems. I know a time or two I’ve downloaded something to /tmp during testing, rebooted after making changes and then lost the original data again. This can be changed if you’d like to keep your /tmp files a little bit longer.

Changing the /tmp Cleanup Frequency

The default setting that tells your system to clear /tmp at reboot is held in the /etc/default/rcS file. The value we’ll look at is TMPTIME.

The current value of TMPTIME=0 says delete files at reboot despite the age of the file. Changing this value to a different (positive) number will change the number of days a file can survive in /tmp.

TMPTIME=7

This setting would allow files to stay in /tmp until they are a week old, and then delete them on the next reboot. A negative number (TMPTIME=-1) tells the system to never delete anything in /tmp. This is probably not something you want, but is available.

Answer 3

The cleaning of /tmp is done by the upstart script /etc/init/mounted-tmp.conf. The script is run by upstart everytime /tmp is mounted. That basically means at every boot.

The script does roughly the following: if a file in /tmp is older than $TMPTIME days it will be deleted.

$TMPTIME is an environment variable defined in /etc/default/rcS. The default value of $TMPTIME is 0, which means every file and directory in /tmp gets deleted.

Answer 4

It is cleaned up every time you reboot.

Answer 5

On one of our servers running Ubuntu, we have a script to remove files in /tmp and it runs nightly.

The script is:

#!/bin/sh
# Clean file and dirs more than 3 days old in /tmp nightly

/usr/bin/find /tmp -type f -atime +2 -mtime +2  |xargs  /bin/rm -f &&

/usr/bin/find /tmp -type d -mtime +2 -exec /bin/rm -rf '{}' \; &&

/usr/bin/find /tmp -type l -ctime +2 |xargs /bin/rm -f &&

/usr/bin/find -L /tmp -mtime +2 -print -exec rm -f {} \;

Just save the contents above to a file chmod 775 the file and create a cron entry to run it. Since this is a web server we don't want to reboot it for obvious reasons.