Create a new swap file of size 512 MiB at /swapfile, activate it, and make...

Solution:

dd if=/dev/zero of=/swapfile bs=1M count=512

chmod 600 /swapfile

mkswap /swapfile

swapon /swapfile

echo "/swapfile swap swap defaults 0 0" > > /etc/fstab

swapon --show

Detailed Explanation:

dd creates the file.

chmod 600 protects swap contents.

mkswap prepares the file as swap.

swapon activates it now.

/etc/fstab ensures it is enabled at boot.