OK - So I was told that the /tmp directory was a place I can throw stuff that is just kind of like a Recycle Bin and that Linux will auto flush this directory at some point. My question is if I move something into /tmp as "root", how long will it remain in /tmp? Does it get flushed automatically by how long it remains in /tmp or does /tmp have a size limit and once exceeded, it flushes the files?

Also can you set parameters for /tmp like auto flush every 30 days or even every 1 day?

Thanks!

On most Linux systems there is an entry in the daily crontab, that every day look for files which have not accessed for a period of time (using tmpwatch) and remove them.

To amplify on that response. /tmp itself is just a directory (or sometimes a filesystem). As such it doesn't automatically delete anything.

On Linux as the above poster said by default many distros have the tmpwatch to do cleaning. On UNIX systems some people add cron jobs to do such cleaning or startup jobs. (Years ago on AT&T UNIX the default job actually blew away the directory on reboot then recreated it.) The idea is NOT to use it for permanent storage as most admins know it is fair game and will not hesitate to blow away files there if space becomes an issue. It's a good to periodically blow things away by such a cron job as at it teacher users not to store things there the hard way.

Note there also is a /var/tmp and on some older systems a /usr/tmp.

Be aware that /tmp is sometimes mounted as tmpfs, i.e. a filesystem backed by virtual memory instead of directly a disk partition.

This is very good for performance, as you'll have memory access time vs disk drive access time for the temporary data placed there.

The drawback are:
- everything is lost when the system shutdowns
- very big files living in /tmp can dramatically slow down the system because of pagination.

Another point: /var/tmp is a filesystem designed to store persistant data. Only the application that create files or directory there are allowed to remove them.
You should't remove files present there (or have a daemon that do it) without knowing what you are removing.

Thanks all!