• WP-CLI
• Bash
• Crontab

This shell script creates the directory wp-backup/, and makes the zip file that includes plugins/ themes/ uploads/ wordpress.sql(Exported mysql data).You can set the maximum number of zip files. This script will delete oldest zip file when file's number reaches the limit.

Also, it will updates WordPres's core, plugins, themes, language file.

1. Please place wp-backup.sh at under　your WordPress directory.
2. Set BACKUP_NUM that is Maximum number of backup files. Also change BASE_DIR to your WordPres's path.
3. Set crontab to schedule of backup.

Fomula

*     *     *     *     *  command to be executed
-     -     -     -     -
|     |     |     |     |
|     |     |     |     +----- day of week (0 - 6) (Sunday=0)
|     |     |     +------- month (1 - 12)
|     |     +--------- day of month (1 - 31)
|     +----------- hour (0 - 23)
+------------- min (0 - 59)

https://help.ubuntu.com/community/CronHowto

Create schedule of task.

$ crontab -e
00 05 * * * ~/apps/wordpress/cron/wp-backup.sh

See the tasks that have already created.

$ crontab -l
00 05 * * * ~/apps/wordpress/cron/wp-backup.sh