Mount a Raspberry Pi image of your choice :)

mount_pi_image.sh

#!/bin/bash

# Globals
TIMESTAMP=$(date +%s)
MOUNT_DIR="/mnt"
BASE_MOUNT_DIR="$MOUNT_DIR/image_$TIMESTAMP"
MOUNT_IMAGE=""

# Usage declaration
display_usage() {
cat << EOF

    Usage: sudo $0 [options]

    [required]
    -i  /path/to/image      Path to the disk image to be mounted/modified

    [optional]
    -f  my_folder_name      Folder to mount the specified image (via the -i flag) at within the $MOUNT_DIR directory

    [extra]
    -h                      Brings up this help screen

EOF
exit $1
}

# Error message handler
error() {
    printf "\n    Error: $1\n"
    display_usage 1
}

# Check the script is running as root
if [[ $EUID -ne 0 ]]; then
    error "Please check that the script is running as root"
fi

# Check, process and validate parameters
while getopts "f:hi:" flag; do
    case "${flag}" in
        f)
            # Validate that the mount directory doesn't already exist

            BASE_MOUNT_DIR="$MOUNT_DIR/${OPTARG}"

            if [ -d "$BASE_MOUNT_DIR" ]; then
                error "$BASE_MOUNT_DIR already exists"
            fi
        ;;
        h)
            # Display help...

            display_usage 0
        ;;
        i)
            # Validate that the image is indeed a valid file

            MOUNT_IMAGE="${OPTARG}"

            if [ ! -f "$MOUNT_IMAGE" ]; then
                error "$MOUNT_IMAGE is not a valid file"
            fi
        ;;
        *)
            # What happened!

            display_usage 0
        ;;
    esac
done

# Set the mount directories
BOOT_MOUNT_DIR="$BASE_MOUNT_DIR/boot"
ROOT_MOUNT_DIR="$BASE_MOUNT_DIR/root"

echo 'Capturing partition details...'
BOOT_PARTITION=`fdisk -l "$MOUNT_IMAGE" | grep "c W95 FAT32 (LBA)"`
ROOT_PARTITION=`fdisk -l "$MOUNT_IMAGE" | grep "83 Linux"`

echo 'Capturing sector size...'
SECTOR_SIZE=`fdisk -l "$MOUNT_IMAGE" | grep "Sector size" | awk '{print $7}'`

echo 'Getting the starting sector of the partitions...'
BOOT_START_SECTOR=`echo "$BOOT_PARTITION" | awk '{print $2}'`
ROOT_START_SECTOR=`echo "$ROOT_PARTITION" | awk '{print $2}'`

echo 'Calculating the starting byte of the partitions...'
((BOOT_START_BYTE=$BOOT_START_SECTOR * $SECTOR_SIZE))
((ROOT_START_BYTE=$ROOT_START_SECTOR * $SECTOR_SIZE))

echo 'Getting the sector length of the partitions...'
BOOT_SECTOR_LENGTH=`echo "$BOOT_PARTITION" | awk '{print $4}'`
ROOT_SECTOR_LENGTH=`echo "$ROOT_PARTITION" | awk '{print $4}'`

echo 'Calculating the byte length of the partitions...'
((BOOT_BYTE_LENGTH=$BOOT_SECTOR_LENGTH * $SECTOR_SIZE))
((ROOT_BYTE_LENGTH=$ROOT_SECTOR_LENGTH * $SECTOR_SIZE))

echo 'Creating mount directories...'
sudo mkdir -p "$BOOT_MOUNT_DIR"
sudo mkdir -p "$ROOT_MOUNT_DIR"

echo 'Mounting partitions...'
mount -v -o offset=$BOOT_START_BYTE,sizelimit=$BOOT_BYTE_LENGTH -t vfat "$MOUNT_IMAGE" "$BOOT_MOUNT_DIR"
mount -v -o offset=$ROOT_START_BYTE,sizelimit=$ROOT_BYTE_LENGTH -t ext4 "$MOUNT_IMAGE" "$ROOT_MOUNT_DIR"

# Done!
exit 0