How to add swap file

README.md

sudo swapon -s
free -m
df -h
sudo fallocate -l 4G /swapfile
ls -lh /swapfile
sudo chmod 600 /swapfile
ls -lh /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
sudo swapon -s
free -m
sudo nano /etc/fstab
Add the line /swapfile   none    swap    sw    0   0

Reference https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04