How many types of backup are there in Linux?

Related questions

1. How does Ubuntu backup work?
2. What is rsync backup?
3. What rsync does in Linux?
4. What is the rsync command?
5. Is it backup or back up?
6. How do I restore Ubuntu to a previous date?
7. What is duplicity backup?
8. What is backup and restore procedure?
9. What is normal backup?
10. Which is better rsync or btrfs?

Tags

1. #folder
2. #different
3. #common
4. #there
5. #backup
6. #single
7. #types
8. #backed
9. #system
10. #every
11. #implies