how do I clear the swap? I know it isn't something that is needed, but I still want to know how to do it. this is what I'm doing so far:
# to check if there is enough space in ram for the swap contents:
free -m
sudo swapoff -a
sudo chmod 600 /var/swap
sudo mkswap /var/swap
sudo swapon -a
that works for clearing the swap, but it doesn't turn on again because it isn't being used until I reboot.
1. Without systemd
You can disable swap with swapoff -a. If swap is being used it is not an instantaneous action (see man swapoff).
If you have defined swap in /etc/fstab you can use swapon -a to activate all known swap files and partitions. If none is defined there you need to declare the swap space that you want to use, for example swapon /var/swap.
There is no need to recreate it each time you want to use it
2. With systemd
The new method for activating swap is through a systemd service, run at boot. You can see its status, for example,
systemctl status dphys-swapfile # What happened last time it ran
systemctl restart dphys-swapfile # Recompute the swapfile space and reactivate it
In turn, systemd calls the dphys-swapfile command (see man dphys-swapfile), which computes a reasonably sized swapfile partition and activates it, or deactivates it, as required.
For example,
dphys-swapfile swapoff # Stop using the swapfile
dphys-swapfile setup # (Re-)compute an optimal swap space as /var/swap
dphys-swapfile swapon # Start using the computed swapfile
In the systemd and dphys-swapfile world, swapspace defaults to the file /var/swap rather than a partition
You are almost there. Before clearing swap, you must unmount it first. In most cases, swap is already defined in the /etc/fstab file. Follow these steps to avoid rebooting your system:
sudo swapoff -a
sudo umount /var/swap
sudo chmod 600 /var/swap
sudo mkswap /var/swap
sudo swapon -a
sudo mount -a
swapoff -a. Since you already know that I'm not clear what it is that you're asking