From FHS: > The /var/tmp directory is made available for programs that require temporary files or directories that are preserved between system reboots. Theref

From FHS: > The /var/tmp directory is made available for programs that require temporary files or directories that are preserved between system reboots. Therefore, data stored in /var/tmp is more persistent than data in /tmp. > Files and directories located in /var/tmp must not be deleted when the system is booted. Although data stored in /var/tmp is typically deleted in a site-specific manner, it is recommended that deletions occur at a less frequent interval than /tmp. * https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s15.html https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch05s15.htm... IRIX docs: > The directories /usr/tmp.O, /var/tmp, and /var/spool/uucppublic are public directories; people often use them to store temporary copies of files they are transferring to and from other systems and sites. Unlike /tmp, they are not cleaned out when the system is rebooted. The site administrator should be even more conscientious about monitoring disk use in these directories. * http://rsusu1.rnd.runnet.ru/sgi/advanced/ch8.html http://rsusu1.rnd.runnet.ru/sgi/advanced/ch8.html From FreeBSD 1.0 (July 1991): /var […] tmp/ temporary files not removed between system reboots vi.recover/ recovery files for the vi(1) editor * https://man.freebsd.org/cgi/man.cgi?query=hier&sektion=7&manpath=FreeBSD+1.0-RELEASE https://man.freebsd.org/cgi/man.cgi?query=hier&sektion=7&man... This is also true for Solaris, which I used to admin many moons ago. So I'm not sure where the idea that /var/tmp gets cleaned on reboot came from since I have always understood it to be fairly static.