Htydjtk

so after committing the infamous mistake of deleting my entire file system via sudo rm -rf /*, recovering from the horrendous damage that i had done and coping with the fact that i just lost 6 years off my lifespan, i started wondering why is it even possible to do that, and what could be done to prevent this mistake from happening.

One solution that i was suggested is revoking root access from my account, but that is inconvenient, because a lot of commands require root access and when you have to run a few dozen commands every day that gets annoying.

Backing up your system is the obvious way to go but restoring a backup also requires some downtime, and depending on your system that downtime could be days or weeks, which could be unacceptable in some cases.

So my question is: Why not implement a confirmation when the user tries to delete his filesystem? So that way when you actually want to do that, you just hit Y or enter, and if you don't at least you don't loose everything.

Meet safe-rm, the “wrapper around the rm command to prevent accidental deletions”:

safe-rm prevents the accidental deletion of important files by
replacing rm with a wrapper
which checks the given arguments against a configurable blacklist of files and directories
which should never be removed.

Users who attempt to delete one of these protected files or directories will not be able
to do so and will be shown a warning message instead. (man safe-rm)

If the installation link above doesn’t work for you just use sudo apt install safe-rm instead.
The default configuration already contains the system directories, let’s try rm /* for example:

$ rm /*

safe-rm: skipping /bin

safe-rm: skipping /boot

safe-rm: skipping /dev

safe-rm: skipping /etc

safe-rm: skipping /home

safe-rm: skipping /lib

safe-rm: skipping /proc

safe-rm: skipping /root

safe-rm: skipping /sbin

safe-rm: skipping /sys

safe-rm: skipping /usr

safe-rm: skipping /var

…

For the cases where you run rm without sudo (which ignores aliases) and the -f flag it’s a good idea to add an alias for your shell that makes rm’s -i flag the default. This way rm asks for every file before deleting it:

alias rm='rm -i'

A similarly useful flag is -I:

prompt once before removing more than three files, or when removing
recursively;
less intrusive than -i, while still giving protection against most mistakes

Confirmation is already there, the problem is the f of the command, that is --force; When user force an operation it is suppose it's know what is doing (obviously a mistake could always append).

an example:

 rm -r ./*

 rm: remove write-protected regular file './mozilla_mvaschetto0/WEBMASTER-04.DOC'? N

 rm: cannot remove './mozilla_mvaschetto0': Directory not empty

 rm: descend into write-protected directory './pulse-PKdhtXMmr18n'? n

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-bolt.service-rZWMCb'? n

 rm: descend into write-protected directory './systemd-private-     890f5b31987b4910a579d1c49930a591-colord.service-4ZBnUf'? n

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-fwupd.service-vAxdbk'? n

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-minissdpd.service-9G8GrR'? 

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-ModemManager.service-s43zUX'? nn

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-rtkit-daemon.service-cfMePv'? n

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-systemd-timesyncd.service-oXT4pr'? n

 rm: descend into write-protected directory './systemd-private-890f5b31987b4910a579d1c49930a591-upower.service-L0k9rT'? n

it is different with --force option, I will not get any confirmation and files are deleted.

The Problem is to know the command and its parameters, navigate more in the man of a command (also if the command is found in a tutorial) for examples: the first time I sow the command tar xzf some.tar.gz I'm asking to my self, what xzf mean?

Then I red the man of tar and discover it.

If your system file space usage isn't immense (and these days 'immense' means 'hundreds of gigabytes or more') create some virtual machine instances, and always work inside of one. Recovery would just entail using a backup instance.

Or you could create a chroot jail, and work inside it. You'd still need some recovery if it got trashed, but that would be easier with a running (enclosing) system to work from.

Well the short answer is to not run such a command.

The long story is that it's part of the customization. Essentially there are two factors at play here. One is the fact that you are free to modify all files.

The second is that the rm command offers the helpful syntactic sugar to delete all files under a folder.

Effectively this could be restated as a singe simple tenet of Unix machines. Everything is a file. To make matters better, there are access controls, but there are overridden by your usage of

sudo

I guess you could add an alias or a function to ensure that this can never be run.

Be wary of using /* with the rm at all. It might be tedious to remove things one folder at a time, but remove all could create a tedious restore from backup. Because of course you backed up.