Argthtjtr

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.

Running without backups means you have to be super careful to never make any mistakes. And hope your hardware never fails. (Even RAID can't save you from filesystem corruption caused by faulty RAM.) So that's your first problem. (Which I assume you've already realized and will be doing backups in the future.)

But there are things you can do to reduce the likelihood of mistakes like this:

• alias rm='rm -I' to prompt if deleting more than 3 things.


• alias mv and cp to mv -i and cp -i (many normal use-cases for these don't involve overwriting a destination file).


• alias sudo='sudo ' to do alias expansion on the first argument to sudo
  

I find rm -I is a lot more useful than rm -i. It usually don't prompt during normal use, so tetting prompted when you didn't expect it is a lot more noticeable / better warning. With -i (before I discovered -I), I got used to typing rm to disable alias expansion, after being sure I'd typed the command correctly.

You don't want to get in the habit of relying on rm -i or -I aliases to save you. It's your safety line that you hope never gets used. If I actually want to interactively select which matches to delete, or I'm not sure if my glob might match some extra files, I manually type rm -i .../*whatever*. (Also a good habit in case you're ever in an environment without your aliases).

Defend against fat-fingering Enter by typing ls -d /*foo* first, then up-arrow and change that to rm -r after you've finished typing. So the command line never contains rm -rf ~/ or similar dangerous commands at any point. You only "arm" it by changing ls to rm with control-a, alt-d to go to the start of the line and adding the -r or the -f after you've finished typing the ~/some/sub/dir/ part of the command.

Depending on what you're deleting, actually run the ls -d first, or not if that wouldn't add anything to what you see with tab-completion. You might start with rm (without -r or -rf) so it's just control-a / control-right (or alt+f) / space / -r.

(Get used to bash/readline's powerful editing keybindings for moving around quickly, like control-arrows or alt+f/b to move by words, and killing whole words with alt+backspace or alt+d, or control-w. And control-u to kill to the beginning of the line. And control-/ to undo an edit if you go one step too far.
And of course up-arrow history that you can search with control-r / control-s.)

Avoid -rf unless you actually need it to silence prompts about removing read-only files.

Take extra time to think before pressing return on a sudo command. Especially if you don't have full backups, or now would be a bad time to have to restore from them.