create/remove swap space

create_swap.sh

#!/bin/sh

# size of swapfile in megabytes
swapsize=512

# does the swap file already exist?
grep -q "swapfile" /etc/fstab

# if not then create it
if [ $? -ne 0 ]; then
        echo 'swapfile not found. Adding swapfile.'
        fallocate -l ${swapsize}M /swapfile
        chmod 600 /swapfile
        mkswap /swapfile
        swapon /swapfile
        echo '/swapfile none swap defaults 0 0' >> /etc/fstab
else
        echo 'swapfile found. No changes made.'
fi

# output results to terminal
cat /proc/swaps
cat /proc/meminfo | grep Swap

remove_swap.sh

#!/bin/sh

# does the swap file exist?
grep -q "swapfile" /etc/fstab

# if it does then remove it
if [ $? -eq 0 ]; then
	echo 'swapfile found. Removing swapfile.'
	sed -i '/swapfile/d' /etc/fstab
	echo "3" > /proc/sys/vm/drop_caches
	swapoff -a
	rm -f /swapfile
else
	echo 'No swapfile found. No changes made.'
fi

# output results to terminal
cat /proc/swaps
cat /proc/meminfo | grep Swap