Swap

The swap simulate RAM "extended". Avoid using it on HDD (tend to slow the computer).

Add swap

dd if=/dev/zero of=/swapfile bs=64M count=16
mkswap /swapfile
swapon /swapfile

Note: Add 1GB swap (64 * 16)

Remove swap

swapoff /swapfile stat -c %y test.txt
rm /swapfile