how to automatically clean /tmp

[Jon LaBadie]

On Wed, Jan 27, 2016 at 08:29:57PM +0100, Walter Cazzola wrote:
> Dear Linux Experts,
> 
> I've recently passed from Fedora 20 to Fedora 23 on my laptop.
> 
> I've a separate partition for /tmp that I'm used to see it wiped out at
> any reboot on my previous installation but now this is never wiped out.
> 
> This is a real partition:
> 
>   /dev/sda10       5029504   1154204   3596772  25% /tmp
> 
> whereas previously it was a tmpfs partition. I've read on the web that
> after Fedora 20 the tmpfs has been dropped in favor of real partition
> but I was expecting anacron/cron entry that wipe the content of the
> partition at boot but my system doesn't have any.
> 
> It is also difficult to create my own anacron/cron entry because this
> should take effect before the system starts and create its temp
> files/sockets in there.
> 
> I'm also puzzled because I also have a couple of tmpfs partitions:
> 
>   tmpfs            1633640         0   1633640   0% /run/user/989
>   tmpfs            1633640        16   1633624   1% /run/user/526
> 
> that I don't what they are for and if I can (and how) rid of them.
> 
> Probably I could add an entry like this
>   tmpfs                   /tmp            tmpfs           rw,seclabel 0 0
> 
> in /etc/fstab but this would means a waste of the space I currently have
> reserved for /tmp (4Gb not much but I would prefer to use them).
> 
> So there is a way to wipe out the /tmp partition before it has been
> mounted and the system creates its files and use the current partition
> for it?

Couple of points.  I don't think you can reserve a partition for the
use of a tmpfs.  It uses your RAM memory and swap space instead.

You could add /dev/sda10 as another swap partition.  Then perhaps add
the fstab entry.  However, I think systemd has a way mount /tmp as a
tmpfs without having an fstab entry.

If you want to use your partition as /tmp but have it cleaned out at
boot, check the manpage for tmpfiles.d

Jon
-- 
Jon H. LaBadie                  jonfu at jgcomp.com