How to enable/disable/empty the swap

My Sabayon seems to have the habit of writing stuff into the swap and then forgetting about them. So I thought for a while, why not just empty the swap when it's full and I'm sure nothing is using it. Well, it turned out it's possible to do so. Thanks to this forum post, now I know how.
So, there are the commands:
>$swapoff
>$swapon
which can be safely used to turn on and off the swap. Now, the source site suggests using ">$swapoff /dev/hdxx" but if you have only one swap partition (like I do) this is unnecessary.
All you need to do is (as sudo, of course):
>$swapoff -a
and after it finishes emptying your swap,
>$swapon -a
And it's done. You have a fresh swap file, which you can start trashing immediately.
Now, if you do that when a program is still writing to the swap, I don't know what will happen. Maybe something ugly, maybe not. I tested it when nothing was using the swap even though my ram was almost full, and I haven't noticed any problems for now.
Enjoy!

Radio in Linux

I'm a big fan of listening to radio, so for me, it was very important to have a way to listen to may favorite stations while I'm working on my laptop.
So, to listen to online radio in Linux, you need very few things.
Mainly:
GStreamer (python-gst >= 0.10) for the audio processing.
Using GStreamer, you can play radio from url using:
$gst-launch-0.10 playbin uri=http://ns57.ovh.net:80/
In this example, the radio is Alouette, a French radio. Of course,  you can use any kinds of streaming url-s.
If you need an application to play your favorite radio stations, you can use pretty much all the players, and if you install the package kradio, you can also receive information about the song being played in real time.
Finally, an application I found just today is radiotray-0.6.4. It is very sweet and light (28Mb right now), it installs a tray, from where you can change easily all the stations you like. You can also add stations using the gui, to sort them, put them in different groups and so on. If you're not such a fan of gui or you want to import a larger list, then the config files are found in
~/.local/share/radiotray/
There are two files, from where you can set up the configs of the player and also the PLAYLIST.
Just open bookmarks.xml with your favorite text editor and use
<group name="My stations">
 <bookmark name="cherieFM" url="http://mp3.live.tv-radio.com/cherie_fm/all/che_124310.mp3"/> 
<bookmark name="NRJ Hits" url="http://mp3.live.tv-radio.com/nrj_hits/all/nrj_150726.mp3"/> 
</group>
to list your favorite stations and order them in whatever way you find suitable.
Enjoy!

How to convert png to pdf

Ok, as always Libre Office Impress does strange things with slides design when I do export to PDF so I got creative.
1. Export to PNG from File->Export (you could do it for all slides trough Export->Html, but somehow the quality appears worst)
2. Make sure you name you pngs correctly: Pic001.png, Pic002.png
3.  convert Pic0*.png -quality 100 document.pdf
Et voila!
Now, convert has some pretty cool options, make sure to check the man pages if you want to do something more fancy.
Another cool thing I discovered is how to convert png to eps!

sam2p pic1.png EPS:pic1.eps (source)
It works awesomely and makes even 3d plots look good. Of course, you could use also convert:

convert fig.png eps3:fig.eps 

(source)
Nice huh?