Run folloing command on CLI to create new swap file size: 1024M, you should change this size by your seft.
/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1
Resize swap:
/sbin/swapoff /var/swap.1
/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=4096
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1
To start swap at boot
sudo cp /etc/fstab /etc/fstab.bak
echo '/var/swap.1 none swap sw 0 0' | sudo tee -a /etc/fstab
Above example to create swap.1 file and this file located at /etc/, futhermore swap file such as swap.2, swap.3, swap.4,…you could do the same way just need to change this swap file name.