#!/bin/bash

#mount_dir="$(mktemp -d /tmp/ramdisk.XXXX)"
mount_dir="/tmp/ramdisk"
mkdir "$mount_dir"
img_file="$mount_dir/img"

if [[ ! -f "$1" ]]; then
    echo "'$1' is an invalid file"
    exit 1
fi

# create tmpfs and copy the file on it
img_size="$(stat --printf="%s" "$1")"
sudo mount -t tmpfs size=$img_size,noexec,nosid,uid=$UID,gid=$GID "$mount_dir"
cp "$1" "$img_file"

read -p "press enter to unmount"

# check if the file is in use
while lsof "$mount_dir" | grep -q "$mount_dir"; do
    echo "Device is busy"
    read -p "press enter to unmount"
done

# save the image to disk
if cp "$img_file" "$1.tmp"; then
    mv "$1.tmp" "$1"
else
    echo "Error copying '$img_file' back to disk!"
    exit 1
fi

# cleanup
sudo umount "$mount_dir"
rmdir "$mount_dir"