dropbox-backup.sh - script to backup dropbox via rclone

dropbox-backup.sh

#!/usr/bin/env bash
set -euo pipefail

# ── dropbox-backup ───────────────────────────────────────────────────────────
# Ad-hoc, on-demand backup of the ENTIRE Dropbox account to the LaCie drive.
#
# Pulls straight from the Dropbox cloud over the API via rclone. It does NOT
# read, touch, or depend on the local Dropbox sync folder
# (~/Library/CloudStorage/Dropbox), so it can't disturb normal Dropbox sync,
# and it also captures the ~4k files that are currently "online only".
#
# Layout created on the drive:
#   /Volumes/LaCie/Dropbox-Backup/current/           exact mirror of Dropbox now
#   /Volumes/LaCie/Dropbox-Backup/_archive/<stamp>/  files that were deleted or
#                                                    replaced, kept per run
#   /Volumes/LaCie/Dropbox-Backup/logs/<stamp>.log   full rclone log per run
#
# Nothing is ever permanently deleted from the drive: a file removed or changed
# in Dropbox is moved into that run's _archive/ folder before the mirror is
# updated.
#
# Usage:
#   dropbox-backup                real run
#   dropbox-backup --dry-run      show what would change, transfer nothing
#   dropbox-backup --help
# Extra arguments are passed straight through to `rclone sync`
# (e.g. --dry-run, --bwlimit 20M, --verbose).
# ────────────────────────────────────────────────────────────────────────────

REMOTE="dropbox:"
MOUNT="/Volumes/LaCie"
DEST="$MOUNT/Dropbox-Backup"

MIRROR="$DEST/current"
STAMP="$(date +%Y-%m-%d_%H%M%S)"
ARCHIVE="$DEST/_archive/$STAMP"
LOGDIR="$DEST/logs"
LOG="$LOGDIR/$STAMP.log"

c_red=$'\033[31m'; c_grn=$'\033[32m'; c_cyn=$'\033[36m'; c_off=$'\033[0m'
info() { printf '%s▸ %s%s\n' "$c_cyn" "$*" "$c_off"; }
die()  { printf '\n%s✗ %s%s\n' "$c_red" "$*" "$c_off" >&2; exit 1; }

case "${1:-}" in
  -h|--help) sed -n '4,27p' "$0" | sed 's/^#\{1,\} \{0,1\}//'; exit 0 ;;
esac

# Create and announce the log file first, before any checks, so it exists
# on disk immediately and you can start tailing it right away.
mkdir -p "$LOGDIR"
: > "$LOG"
info "Log: $LOG"
info "Tail it with: tail -f \"$LOG\""
echo

# ── preflight ───────────────────────────────────────────────────────────────
command -v rclone >/dev/null || die "rclone not installed — run: brew install rclone"

rclone listremotes | grep -qx "$REMOTE" \
  || die "rclone remote '$REMOTE' is not set up. Run once:  rclone config create dropbox dropbox"

[[ -d "$MOUNT" ]] && mount | grep -q " on $MOUNT " \
  || die "LaCie drive is not mounted at $MOUNT — plug it in / unlock it and retry"
[[ -w "$MOUNT" ]] || die "$MOUNT is not writable"

info "Checking the Dropbox remote is reachable…"
rclone lsd "$REMOTE" --max-depth 1 >/dev/null \
  || die "Can't reach Dropbox. Re-authorise with:  rclone config reconnect $REMOTE"

mkdir -p "$MIRROR" "$LOGDIR"

avail_gb="$(df -g "$MOUNT" | awk 'NR==2 {print $4}')"
[[ -n "${avail_gb:-}" && "$avail_gb" -lt 60 ]] \
  && info "WARNING: only ${avail_gb} GB free on the LaCie"

# ── run ─────────────────────────────────────────────────────────────────────
progress=(--stats=30s --stats-one-line)
[[ -t 1 ]] && progress=(--progress)

info "Source : $REMOTE"
info "Mirror : $MIRROR"
info "Archive: $ARCHIVE  (only created if something is removed/changed)"
echo

set +e
rclone sync "$REMOTE" "$MIRROR" \
  --backup-dir "$ARCHIVE" \
  --create-empty-src-dirs \
  --fast-list \
  --modify-window 2s \
  --transfers 8 \
  --checkers 16 \
  --retries 5 \
  --low-level-retries 10 \
  --exclude ".DS_Store" \
  --exclude ".dropbox" \
  --exclude ".dropbox.attr" \
  --log-file "$LOG" \
  --log-level INFO \
  "${progress[@]}" \
  "$@"
rc=$?
set -e

# Remove the archive dir again if this run didn't move anything into it.
[[ -d "$ARCHIVE" ]] && rmdir "$ARCHIVE" 2>/dev/null && \
  info "Nothing was deleted or replaced this run."

echo
if [[ $rc -eq 0 ]]; then
  size="$(du -sh "$MIRROR" 2>/dev/null | cut -f1)"
  printf '%s✓ Backup complete.%s  Mirror is %s on the LaCie.\n' "$c_grn" "$c_off" "${size:-?}"
  [[ -d "$ARCHIVE" ]] && printf '  Archived this run: %s (%s)\n' \
    "$(du -sh "$ARCHIVE" 2>/dev/null | cut -f1)" "$ARCHIVE"
else
  die "rclone exited with code $rc — see $LOG"
fi