Backup and Restore FAT formatted flash drive

fatback.sh

#!/usr/bin/env bash
# FatBack v0.1
#
# Backup and Restore FAT formatted flash drive
# This tool is used for backing up a bootable CompactFlash formatted in FAT32. It will create
# a compressed ZSTD image which can be later restored back.
# 
# Copyright 2021 jeznav
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# NOTICE: This script has not been tested on Hard-disks or any other storage mediums. Not tested on
# Linux, and Windows WSL. USE AT YOUR OWN RISK!
#
## Usage: 
##
##

arg1=$1
SOURCE_DEVICE=""
TARGET_NAME=""

check_os(){
    if [ "$(uname)" != "Darwin" ]; then 
        echo "This script only runs on macOS!"
        exit 1
    fi
    echo "Checking for sudo...$EUID"
    if [ "$EUID" != 0 ]; then 
        echo "Please run this script in sudo!"
        exit 1
    fi
}

check_tools() {
    printf "Checking for %s..." "$1"
    if which "$1" &>/dev/null; then echo "Ok"; else echo "not found. Aborting! $2"; exit 1; fi
    sleep 0
}

help(){
    echo "Usage: $0 device"
}

version(){
    echo "FatBack v0.1 (C) 2021 jeznav"
}

show_devices(){
    diskutil list | grep -e 'image\|external\|FAT'
}

verify_device(){
    echo "Listing FAT devices:"
    show_devices
    if ! show_devices | grep "$1" &>/dev/null; then
        echo "Could not find $1";
        exit 1
    else
        while true; do
            SOURCE_DEVICE=$(show_devices | grep "$1" | cut -d' ' -f1)
            read -r -p "Is the source device $SOURCE_DEVICE correct? " yn
            case $yn in
                [Yy]* ) true; break;;
                [Nn]* ) echo "Aborting..."; exit;;
                    * ) echo "Please answer yes or no.";;
            esac
        done
    fi
}

select_target_name(){
    identifier=$(echo "$1" | cut -d'/' -f3)
    TARGET_NAME=$(show_devices | grep "$identifier" | grep "FAT" | awk '{print $3}')
    SOURCE_SIZE=$(show_devices | grep "$identifier" | grep "FAT" | awk '{print $4}' | cut -d'.' -f1)
    while true; do
        read -r -p "Do you want to use $TARGET_NAME as target filename? (Yes/No/Cancel) " ync
        case $ync in
            [Yy]* ) true; break;;
            [Nn]* ) read -r -p "Enter target filename: " TARGET_NAME; break;;
            [Cc]* ) echo "Canceling..."; exit;;
                * ) echo "Please answer yes or no.";;
        esac
    done    
}


dump_device(){
    echo "Dumping $SOURCE_DEVICE to $TARGET_NAME.img ..."
    dd bs=1m if="/dev/rdisk2" | pv -s "$SOURCE_SIZE"G | dd of="$TARGET_NAME.img" 
    #dd if="$SOURCE_DEVICE" | pv -s "$SOURCE_SIZE"G | dd of="$TARGET_NAME.img" 
}

mount_image(){
    echo "Mounting Image"
}

zero_fill(){
    echo "Zeroing empty spaces..."
}

get_used_space(){
    echo "Getting used spaced..."
}

unmount_image(){
    echo "Unmounting image..."
}

trim_image(){
    echo "Trimming image..."
}

initialize(){
    clear
    check_os
    check_tools "dd"
    check_tools "zstd" 
    check_tools "mtools" "Please install mtools via homebrew -> 'brew install mtools'"
    check_tools "pv" "Please install pv via homebrew -> brew install pv"
    verify_device "$1"
    select_target_name "$SOURCE_DEVICE"
    while true; do
        read -r -p "Ready to dump $SOURCE_DEVICE to $TARGET_NAME.img? " ync
        case $ync in
            [Yy]* ) true; break;;
            [Nn]* ) echo "Aborting..."; exit;;
            [Cc]* ) echo "Canceling..."; exit;;
                * ) echo "Please answer yes or no.";;
        esac
    done
    dump_device
}

if [ -z "$arg1" ]; then 
    help
else
    if [[ "$arg1" == *"/dev/"* ]]; then
        initialize "$arg1"
    else
        echo "Invalid syntax!"
        help
    fi
fi