this post was submitted on 08 Dec 2023
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Linux

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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.

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Can one recover from an accidental rm -rf of system directories by copying those files back in from a backup? (lemmy.ml)
submitted 11 months ago* (last edited 11 months ago) by HiddenLayer5@lemmy.ml to c/linux@lemmy.ml
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Well I've joined the "accidentally trashing your system with rm -rf" club! Luckily I didn't delete my home directory with all the things I care about, but I did delete /boot and /usr, and maybe /var (long story, boils down to me trying to delete non-system directories named those but reflexively adding the slash in front when I should not have). I have backups of those as well, so what are my prospects of recovering from this by just copying them back in using a live USB? Only issue is they're stored in my server as belonging to the server user (I assume everything in those directories should belong to root and I can just use chown?) But I also don't know if they retain the same permissions when backed up.

Has anyone had any luck recovering a system in this way? I'm hoping not to have to reinstall everything because I had gotten pretty cozy with the current installation.

UPDATE: I finally had the time to sit down and try it, and, I was at least hoping to document some glitchy or unstable behaviour but it just didn't work at all. No matter what I tried I couldn't even get the UEFI to recognize the old system as bootable, so I cut my losses and just reinstalled. Gonna make sure I have btrfs snapshotting enabled this time, which I'm realizing I probably should have done in the first place.

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[–] bizdelnick@lemmy.ml 3 points 11 months ago

No way, reinstall.

If even file owner is not preserved (it is not always root, espetially in /var), you likely lost files' extanded attributes an, maybe, also permissions. Without them your system won't work normally.

Then, contents of these directories must be consistent with other ones. E. g. /var contains a package manager data about packages you installed. If you installed/removed anything after creating a backup, information about this will be lost.

If you created the backup while system was working, some files (espetially under /var, again) could be changed during that process, and this also makes such backup unusable. Every sysadmin knows that to create a database backup by copying files, dbms must be stopped.

In future, think about restoration before planning a backup and test if this possible immediately after it is done.