Create Swapfile in Ubuntu

createSwap.sh

#!/bin/bash
regex='^[0-9]+([.][0-9]+)?$'
if [[ ! $2 =~ $regex ]]; then
    echo "Usage: createSwap.sh fullPathToSwapFile swapFileSizeinGB";
    echo "ex: createSwap /tmp/swapfile.swap 8"
    exit 1
fi
if [[ -d $1 ]] || [[ -f $1 ]] || [[ ! $1 = /* ]]; then
    echo "please supply the full path to a new swapFile"
    exit 1
fi

echo "Allocating file space for $1"
sudo fallocate -l $2G $1
echo "done"
sudo chmod 600 $1
# sudo dd if=/dev/zero of=/mnt/1GB.swap bs=1024 count=1048576
sudo mkswap $1
sudo swapon $1
echo "$1  none  swap  sw 0  0" | sudo tee --append /etc/fstab