Mondo archive backup script

mondo-backup.sh

#!/bin/bash
# Backup system with mondoarchive

backupLocation=''
nbrOfBackups=8
ignore='/home|/media|/mnt|/dev|/var/lib/transmission-daemon'
backupPrefix="Backup."

function is_integer() {
  echo "$1" | grep -qE '^[0-9]+$'
  return "$?"
}

function print_script_usage_and_exit() {
  if [ ! -z "$1" ]; then
    echo -e "$1\n" >&2
  fi
  echo "Usage: mondo-backup.sh -l '/path/to/backup' [-n 16]" >&2
  echo "  -l : The backup location directory." >&2
  echo "  -n : The number of backups to keep. Defaults to 16." >&2
  exit 1
}

# parse arguments
while getopts :l:n: option; do
  case "$option" in
    l) backupLocation="$OPTARG" ;;
    n) nbrOfBackups="$OPTARG" ;;
   \?) print_script_usage_and_exit ;;
    :) print_script_usage_and_exit "Error: Option '-$OPTARG' requires an argument" ;;
  esac
done
shift $((OPTIND-1))

# Validate input
if [ -z "$backupLocation" ]; then
  print_script_usage_and_exit "Error: Backup location not specified"
elif [ ! -d "$backupLocation" ]; then
  print_script_usage_and_exit "Error: Backup location '$backupLocation' doesn't exist"
elif ! is_integer "$nbrOfBackups"; then
  print_script_usage_and_exit "Error: Number of backups must be an integer"
fi

# Build work variables
thisBackup="${backupLocation}"/"${backupPrefix}$(date +'%F.%T.%Z')"

# Mondo backup 
mkdir "${thisBackup}"
/usr/sbin/mondoarchive -OVi9 -d "${thisBackup}" -E "${ignore}" >/dev/null 2>/dev/null

# Handle errors
rc="$?"
if [ "$rc" -ne 0 ]; then
    echo -e "Error: Backup failed with error code $rc, deleting it.\n" >&2
    cat /var/log/mondoarchive.log >&2
    rm -rf "${thisBackup}"
    exit "$rc"
fi

cp /var/log/mondoarchive.log "${thisBackup}"

# Delete old backups
IFS=$(echo -en "\n\b")
if [ $(ls -d "${backupLocation}"/"${backupPrefix}"* | wc -l) -gt "${nbrOfBackups}" ]; then
    rm -rf $(ls -d "${backupLocation}"/"${backupPrefix}"* | sort | \
        head -n $(expr $(ls -d "${backupLocation}"/"${backupPrefix}"* | wc -l) - "${nbrOfBackups}"))
fi
unset IFS