KDE SC uses several directories on your filesystem to store temporary files. Most of those files are unneccesary and can be removed when KDE is not running; at least I do that :P

Those directories are (defaults in Gentoo):

• /tmp/kde-$USER
• /var/tmp/kdecache-$USER/
• /tmp/ksocket-$USER/

More information about those directories can be found here.

• If one uses an encrypted filesystem for /home only, sensible data is still accessible in the non encrypted / filesystem.
• Also in a fully encrypted filesystem you may want to have your data in your user directory.
• In my case I don't like the amout of data that is used on my very small / partition.

With environment variables one can tell KDE to use other paths for those directories.

KDE uses KDETMP and KDEVARTMP. To change them while KDE starts, create the file 'changeenv.sh' in $KDEHOME/env:

#!/bin/bash
 
export KDETMP="/home/username/.kde4/temporary/"
export KDEVARTMP="/home/username/.kde4/temporary/"
 
#KDE does not create both directories, they must exist already on KDE's start.
[ -d $KDETMP ] || mkdir -p $KDETMP
[ -d $KDEVARTMP ] || mkdir -p $KDEVARTMP

It is important that the file ends with .sh so KDE really executes it. Technical information about this can be found here.

Do not forget to make it executable:

chmod a+x changeenv.sh

The script checks whether both directories exist and creates them if, because KDE fails to start if they do not exist.

Now you have the following directories in /home/username/.kde4:

• kdecache-username
• kde-username
• ksocket-username

The first directory can be removed from time to time, the last two can be removed on startup/shutdown of your system on a regular basis.