How to add more swap space on Linux

An easy method if you don't want to repartition the whole disk.

dd if=/dev/zero of=/tmp/swap.img bs=1M count=256

Set up a loop device and connect the dummy file with that device:

losetup /dev/loop3 /tmp/swap.img


Then, it's just formatting the loop device:

mkswap /dev/loop3


It also needs activation:

swapon /dev/loop3


Voilá, there is a new swap partition.

To remove it:

swapoff /dev/loop3
losetup -d /dev/loop3
rm /tmp/swap.img


Using apt behind a proxy in Ubuntu

It's really easy. All you have to do is:


http_proxy='http://someproxy:someport"
$export http_proxy


and voila, you can apt-get update, apt-get install, whatever.