encrypted backup to google drive

bup.sh

#!/usr/bin/env bash
# my backup script
# always requires three arguments:
# $1 = "upload" or "recover"
# $2 = encryption key
# $3 = target directory
# ===upload mode===
# Requires ~/.drive folder that das already been setup
# target directory is an absolute path to a folder to be encrypted and uploaded
# Puts backup files into a folder #encfs/targetName in google drive
# ===recover mode===
# target directory is an absolute path to a folder containing encrypted files
# .encfs6.xml (or _encfs6.xml) must be in the top level
# decrypted files will appear in /tmp/decrypted
set -eu -o pipefail

# requires: drive, encfs
# pacaur -Syyu drive encfs

# uncomment this to compute and compare all checksums
#IGNORE_CHECKSUM="-ignore-checksum=false"
IGNORE_CHECKSUM=""

ENCRYPTION_KEY=$2
TARGET="$3"
if [ ! -d "${TARGET}" ]; then
  echo "Error: ${TARGET} does not exist."
  exit -1
fi
TARGET_BASE=$(basename $TARGET)

upload(){
  VIRTUAL_MOUNT="/tmp/encrypted"
  DRIVE_FOLDER="${HOME}/.drive"
  if [ ! -d "$DRIVE_FOLDER/.gd" ]; then
    echo "Error: $DRIVE_FOLDER/.gd does not exist."
    exit -1
  fi

  DRIVE_TARGET="${DRIVE_FOLDER}/#encfs/${TARGET_BASE}"
  if [ -a "$DRIVE_TARGET" ]; then
    echo "Error: $DRIVE_TARGET already exists."
    exit -1
  fi

  mkdir "${VIRTUAL_MOUNT}"
  echo -n "" | \
  encfs --extpass="echo $ENCRYPTION_KEY" --reverse -o ro "${TARGET}" "${VIRTUAL_MOUNT}"
  echo "Here is the encfs config being used here:"
  echo "================="
  cat "${TARGET}/.encfs6.xml"
  echo "================="
  echo "You can also find it here: ${TARGET}/.encfs6.xml"
  mkdir -p "${DRIVE_FOLDER}/#encfs"
  cd "$DRIVE_FOLDER"
  cp "${TARGET}/.encfs6.xml" "#encfs/${TARGET_BASE}_encfs6.xml"
  drive push -directories -no-prompt "#encfs"
  drive push -files -ignore-checksum=false -no-prompt "#encfs"

  ln -s "${VIRTUAL_MOUNT}" "${DRIVE_TARGET}"
  drive push ${IGNORE_CHECKSUM} -no-prompt -quiet "#encfs/${TARGET_BASE}"
  drive cp "#encfs/${TARGET_BASE}_encfs6.xml" "#encfs/${TARGET_BASE}/_encfs6.xml"
  fusermount -u "${VIRTUAL_MOUNT}" && rm -rf "${VIRTUAL_MOUNT}" && rm -rf "${HOME}/.drive/#encfs" && echo "Great success!"
}

recover(){
  VIRTUAL_MOUNT="/tmp/decrypted"
  ENCFS6_CONFIG="${TARGET}/.encfs6.xml"
  cp "${TARGET}/_encfs6.xml" "${ENCFS6_CONFIG}" &>/dev/null || true
  if [ -f "${ENCFS6_CONFIG}" ]; then
    mkdir ${VIRTUAL_MOUNT}
    encfs --extpass="echo $ENCRYPTION_KEY" -o ro "${TARGET}" "${VIRTUAL_MOUNT}"
  else
    echo "Error: ${ENCFS6_CONFIG} not found."
    exit -1
  fi

  echo "Unencrypted data now available readonly at ${VIRTUAL_MOUNT}"
  echo "When you are finished with it, clean up with:"
  echo "fusermount -u ${VIRTUAL_MOUNT} && rm -rf ${VIRTUAL_MOUNT}"
}

$1