my very secret files mount/umount kit

my-crypt-mount.sh

#!/bin/bash

DIR="$(dirname "$(realpath "$0")")"
CREATE=no

while [ -z "$MAP" ]; do
    if [ -n "$1" ]
    then MAP="$1"; shift
    else
        echo current image files:
        ls -1 *.img | xargs -rn1 -IX basename X .img
        echo
        read -ep "MAP=" MAP
    fi
    MAP="$(basename "$MAP" .img)" # make sure we don't end with .img
    IMG="$DIR/$MAP.img"
    if [ ! -f "$IMG" ]; then
        read -ep "create $IMG? " -i y YN
        if [[ "$YN" =~ [Yy] ]]
        then CREATE=yes
        fi
    fi
done

DEV=$(losetup -f) # name of the first unused loopback device

if [ x$CREATE = xyes ]; then
    # set up the initial file
    (set -x; dd if=/dev/zero of=$IMG bs=1M count=10)
fi

(set -x; sudo losetup $DEV "$IMG") || exit 1

if [ x$CREATE = xyes ]; then
    # write random data to thing
    (set -x; sudo badblocks -s -w -t random -v $DEV) || exit 1

    # format with aes
    (set -x; sudo cryptsetup -y luksFormat -c aes -s 256 $DEV) || exit 1
fi

(set -x; sudo cryptsetup luksOpen $DEV $MAP) || exit 1

if [ x$CREATE = xyes ]; then
    # make an ext4 filesystem
    (set -x; sudo mkfs.ext4 /dev/mapper/$MAP) || exit 1
fi

(set -x; sudo e2fsck -f /dev/mapper/$MAP) || exit 1
(set -x; sudo mkdir -vp /mnt/$MAP) || exit 1
(set -x; sudo mount /dev/mapper/$MAP /mnt/$MAP) || exit 1

if [ x$CREATE = xyes ];
then (set -x; sudo chown -cR $(id -u):$(id -g) /mnt/$MAP)
fi

my-crypt-umount.sh

#!/bin/bash

DIR="$(dirname "$(realpath "$0")")"

while [ -z "$MAP" ]; do
    if [ -n "$1" ]
    then MAP="$1"; shift
    else
        echo current image files:
        ls -1 *.img | xargs -rn1 -IX basename X .img
        echo
        read -ep "MAP=" MAP
    fi
    MAP="$(basename "$MAP" .img)" # make sure we don't end with .img
    IMG="$DIR/$MAP.img"
done

(set -x; sudo umount /mnt/$MAP)
(set -x; sudo cryptsetup luksClose $MAP)

#/dev/loop0: []: (/home/very/secret/images/other.img)
#/dev/loop1: []: (/home/very/secret/images/test.img (deleted))
devs=( $(losetup -a | \grep -E "$IMG|\\(deleted\\)" | cut -d: -f1 | grep /dev/loop) )
for DEV in "${devs[@]}"
do (set -x; sudo losetup -d "$DEV")
done
(set -x; sudo rmdir /mnt/$MAP)