Backup The Pc System Simple .

Cron job as a user process: files in "/var/spool/cron/crontabs" directory and restart cron(8). See Section 9.4.14, “Scheduling tasks regularly” for cron(8) and crontab(1).

Systemd timer jobs as user processes: files in "~/.config/systemd/user" directory. See systemd.timer(5) and systemd.service(5).

Autostart jobs as user processes: files in "~/.config/autostart" directory. See Desktop Application Autostart Specification.

Data should be at least on different disk partitions preferably on different disks and machines to withstand the filesystem corruption. Important data are best stored on a read-only filesystem. ^[4]

Sensitive identity data such as "/etc/ssh/ssh_host_*_key", "~/.gnupg/*", "~/.ssh/*", "~/.local/share/keyrings/*", "/etc/passwd", "/etc/shadow", "popularity-contest.conf", "/etc/ppp/pap-secrets", and "/etc/exim4/passwd.client" should be backed up as encrypted. ^[5] (See Section 9.9, “Data encryption tips”.)

Never hard code system login password nor decryption passphrase in any script even on any trusted system. (See Section 10.3.6, “Password keyring”.)

Hardware (especially HDD) will break

Filesystem may be corrupted and data in it may be lost

Remote storage system can't be trusted for security breaches

Weak password protection can be easily compromised

File permission system may be compromised

Automatic scheduled backup with cron job or systemd timer job