See the solution below in Explanation.
Explanation:
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.