First create and intialize the file to hold the swap. In this example we create a 4GB swapfile:

sudo dd if=/dev/zero of=/swapfile bs=1M count=4096 status=progress

Set the appropriate permissions on the file: It should be readable and writable only by root.

sudo chmod 600 /swapfile

Format and enable the swapfile:

sudo mkswap /swapfile

sudo swapon /swapfile

In order to ensure that the swap is enabled at boot we can add an entry to /etc/fstab. You can add the line to fstab manually or using the command:

sudo bash -c "echo /swapfile none swap defaults 0 0 >> /etc/fstab"

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