MySQL backup script

backup.sh

#!/usr/bin/env bash

usage() {
  echo "----------------------------------------------------------------"
  echo "`basename "$0"` -u [username] -p [password] -d [database] -t [target dir]"
  echo "----------------------------------------------------------------"
  echo "       -u, required, database username"
  echo "       -p, required, database password"
  echo "       -d, required, database name"
  echo "       -t, optional, directory to place backup file"
}

while [[ $# > 1 ]]
do
key="$1"
case $key in
    -u|--username)
    USERNAME="$2"
    shift # past argument
    ;;
    -p|--password)
    PASSWORD="$2"
    shift # past argument
    ;;
    -d|--db)
    DATABASE="$2"
    shift # past argument
    ;;
    -t|--target)
    TARGET="$2"
    shift # past argument
    ;;
    --default)
    DEFAULT=YES
    ;;
    *)
      # unknown option
    ;;
esac
shift # past argument or value
done

if [ -z "$USERNAME" ] || [ -z "$PASSWORD" ] || [ -z "$DATABASE" ]; then
  usage;
  exit 1;
fi
if [ -z "$TARGET" ]; then
  TARGET=.
fi

BACKUP_FILE="${DATABASE}.backup.sql"

mysqldump -u ${USERNAME} --password=${PASSWORD} ${DATABASE} > ${TARGET}/${BACKUP_FILE}