Encrypted backup

encrypted-backup.sh

#!/bin/bash
# written by Arthur Furlan <afurlan@valvim.com>

# check program usage
if [ $# -lt 1 ]; then
    echo "Usage: $0 DEVICE"
    exit 1
elif ! [ -e "$1" ]; then
    echo "Error: device '$1' not found."
    exit 2
elif ! [ -b "$1" ]; then
    echo "Error: device '$1' is not a block device."
    exit 3
fi

CRYPT_KEY='/path/secret.key'
CRYPT_LBL='device-label'
MOUNT_DIR='/mnt/mount-dir'
REMOT_SSH='your-backup-user@example.com'
REMOT_DIR='/remote/dir/'
LOCAL_DIR="$MOUNT_DIR/local/dir/"
LOCAL_KEY="/path/to/ssh/key"

is_device_created() {
    dmsetup ls | grep $CRYPT_LBL > /dev/null
    return $?
}

function is_device_mounted {
    mount | grep "$MOUNT_DIR" > /dev/null
    return $?
}

is_device_created
if [ "$?" = "1" ]; then
    echo -n "Creating encrypted device \"$1\"... "
    cryptsetup create $CRYPT_LBL $1 --key-file $CRYPT_KEY && echo 'OK'
else
    echo 'Encrypted device already created... OK'
fi

is_device_mounted
if [ "$?" = "1" ]; then
    echo -n "Mounting device on directory \"$MOUNT_DIR\"... "
    mount $MOUNT_DIR && echo 'OK'
else
    echo 'Device directory already mounted... OK'
fi

echo
echo 'Syncing with remote server... '
rsync -aH -e "ssh -i $LOCAL_KEY" $REMOT_SSH:$REMOT_DIR $LOCAL_DIR && echo 'OK'
echo

is_device_mounted
if ! [ "$?" = "1" ]; then
    echo -n "Umounting device on \"$MOUNT_DIR\"... "
    umount $MOUNT_DIR && echo 'OK'
else
    echo 'Device directory already unmounted... OK'
fi

is_device_created
if ! [ "$?" = "1" ]; then
    echo -n "Removing encrypted device \"$1\"... "
    cryptsetup remove $CRYPT_LBL 2> /dev/null && echo 'OK'
else
    echo 'Encrypted device already removed... OK'
fi

echo -n "Checking if device \"$1\" still is mounted... "
is_device_mounted || echo 'OK'