Change swap size in Ubuntu 18.04

Swap is a special area on your computer, which the operating system can use as additional RAM.
Starting with Ubuntu 17.04, the swap partition was replaced by a swap file. The main advantage of the swap file is easy resizing.

In the following example, we’ll extend the swap space available in the /swapfile from 4 GB to 8 GB.

1. Turn off all swap processes
   sudo swapoff -a
2. Resize the swap
   sudo dd if=/dev/zero of=/swapfile bs=1G count=8
   if = input file
   of = output file
   bs = block size
   count = multiplier of blocks
3. Make the file usable as swap
   sudo mkswap /swapfile
4. Activate the swap file
   sudo swapon /swapfile
5. Check the amount of swap available
   grep SwapTotal /proc/meminfo