Empty swap. Clear swap. Move swap to RAM. Ubuntu.

toggle_swap.sh

#!/bin/bash

function calc_percentage () {
    mem="$1"
    total="$2"
    if [[ $mem -gt 0 ]]; then
        return $((mem * 100 / total))
    else
        return 0
    fi
}

function echo_mem_stat () {
    mem_total="$(free | grep 'Mem:' | awk '{print $2}')"
    free_mem="$(free | grep 'Mem:'  | awk '{print $7}')"
    mem_percentage=$(calc_percentage $free_mem $mem_total)
    swap_total="$(free | grep 'Swap:' | awk '{print $2}')"
    used_swap="$(free | grep 'Swap:' | awk '{print $3}')"
    swap_percentage=$(calc_percentage $used_swap $swap_total)

    echo -e "Free memory:\t$((free_mem / 1024))/$((mem_total / 1024)) MB\t($mem_percentage%)"
    echo -e "Used swap:\t$((used_swap / 1024))/$((swap_total / 1024)) MB\t($swap_percentage%)"
}

echo "Testing..."
echo_mem_stat

if [ "$used_swap" -eq 0 ] || [ "$swap_percentage" -lt 5 ]; then
    echo "No need to free swap"
elif [[ $used_swap -lt $free_mem ]]; then
    echo "Freeing swap..."

    swapoff -a
    swapon -a

    echo_mem_stat
else
    echo "Not enough free memory. Exiting."
    exit 1
fi