A simple backup script using tar.

backup.tar

#!/usr/bin/env sh

# arguments
name="${1}"
src="${2}"
dest_dir="$(dirname "${3}/gets_removed")"

# validate arguments
if [ -z "${name}" ]; then
  echo "Invalid backup name (first argument)"
  exit 1
elif [ ! -d "${src}" ]; then
  echo "Invalid source directory: '${src}'"
  exit 1
elif [ ! -d "${dest_dir}" ]; then
  echo "Invalid destination directory: '${dest_dir}'"
  exit 1
fi

suffix='.tar.gz'
temp_prefix="${dest_dir}/${name}-incomplete-backup-"
temp_dest="${temp_prefix}$(date --utc '+%FT%R:%SZ')${suffix}"
dest="${dest_dir}/${name}-backup${suffix}"

# use pigz if possible, otherwise default to gzip
compression_prog="gzip"
if which pigz > /dev/null 2>&1; then
  # multicore gzip replacement
  compression_prog="pigz"
fi

echo "Backing up to ${temp_dest}"
echo "Using ${compression_prog} for compression"

# do the backup as non-intrusively as possible
nice -n19 ionice -c3 tar \
  --verbose \
  --sort="name" \
  --preserve-permissions \
  --ignore-failed-read \
  --exclude="/dev/*" \
  --exclude="/proc/*" \
  --exclude="/sys/*" \
  --exclude="/tmp/*" \
  --exclude="/run/*" \
  --exclude="/mnt/*" \
  --exclude="/media/*" \
  --exclude="/lost+found/*" \
  --exclude="/home/*/.cache/*" \
  --exclude="/home/*/.config/*chrom*/Default/File System/*" \
  --exclude="/home/*/.config/*chrom*/Default/GPUCache/*" \
  --exclude="/home/*/.dropbox/logs/*" \
  --exclude="/home/*/.local/share/Trash/*" \
  --exclude="/home/*/.mozilla/firefox/*/Cache" \
  --exclude="/home/*/.gvfs" \
  --exclude="/home/*/.thumbnails/*" \
  --exclude="${temp_dest}" \
  --exclude="${dest}" \
  --exclude-backups \
  --exclude-caches \
  --one-file-system \
  --use-compress-program="${compression_prog}" \
  --create \
  --file="${temp_dest}" \
  "${src}"

# if the backup succeeded, replace the old one with the temp version
if [ "$?" -eq 0 ]; then
  echo "Moving ${temp_dest} to ${dest}"
  mv "${temp_dest}" "${dest}"

  # remove any old incomplete backups with an identical prefix
  echo "Removing expired incomplete backups..."
  rm -f ${temp_prefix}*${suffix}

  echo "Backup to ${dest} complete!"
else
  echo "Backup to ${temp_dest} failed (code $?)!"
  exit "$?"
fi