Ubuntu 20 create swap space on disk

create-swap.sh

#!/bin/bash

SIZE="$1"
FILE="/var/swap.img"
SWPS=10
CHPR=50

if [ -z "$SIZE" ]; then
        echo "first argument must be size (fallocate -l)"
        exit
fi

if [ ! -z "$2" ]; then
        FILE="$2"
fi

if [ -f "$FILE" ]; then
        echo "file ${FILE} already exist!"
        exit
fi

fallocate -l "$SIZE" "$FILE"
chmod 600 "$FILE"
mkswap "$FILE"
swapon "$FILE"
echo -e "${FILE}\tnone\tswap\tsw\t0 0" >> /etc/fstab

echo -e "\nvm.swappiness=${SWPS}\nvm.vfs_cache_pressure=${CHPR}" >> /etc/sysctl.conf
sysctl "vm.swappiness=${SWPS}"
sysctl "vm.vfs_cache_pressure=${CHPR}"