On a sunny day (Wed, 26 Feb 2020 20:33:07 +0000) it happened druck
 wrote in :

>On 24/02/2020 11:52, Martin Gregorie wrote:
>> However, it did teach me a lesson, which is that its a very
>> good idea to make a copy of every file you change in /etc and its
>> subdirectories and keep the copies in one of your normal login user.
>
>Even better, install the etckeeper package. This will store all changes
>to files in etc in git repository. When you edit a file, you can either
>manually commit it with a comment explaining what you have done, or if
>you forget it will automatically commit them on a daily cron task. It
>also detects changes made by the package manager, so its easy to find
>out what happened if things go wrong.
>
>---druck

Even better, backup everything on a regular basis
-rw-r--r-- 1 root root 31312576512 Feb 24 16:44
raspi_95_24_2_2020_external_sdcard_reader_verify_OK.img
-rw-r--r-- 1 root root    35482342 Feb 24 17:19
RP4_95_p1-5_external_sdcard_reader.tgz
-rw-r--r-- 1 root root  8197553174 Feb 24 19:03
RP4_95_p2-5_external_sdcard_reader.tgz

The first is an image of the complete card made on an other PC (rp4 off, card
in other PC)
the other two are the tar -zcvf of both partitions of that card,
Easy to unzip one and get any file back.
It is some more work and needs a reboot, but as I modifiy so much
're-install' or 'update' is not in my books.
Practically every image is a new system.

Hijack and encrypt and ask for bitcoins? back in a 'FLASH'.
Bad card? Want a copy for an other raspi4? etc etc..


I identify the raspis here by the last digit of their fixed IP address.
192.168.178.95 is raspi95 etc.

I have backups that go back to almost the original buster install..
You need a couple of huge harddisks... Every backup is on at least 2 different
harddisks\,
one is almost always offline.

This RP4 sees 3.4 TB or so on USB.

raspi95: /mnt/sda2/security/video # df
Filesystem      1K-blocks       Used Available Use% Mounted on
/dev/root        29771644   14467188  14013220  51% /
devtmpfs          1867796          0   1867796   0% /dev
tmpfs             1999892          0   1999892   0% /dev/shm
tmpfs             1999892       8908   1990984   1% /run
tmpfs                5120          8      5112   1% /run/lock
tmpfs             1999892          0   1999892   0% /sys/fs/cgroup
/dev/mmcblk0p1     258095      53032    205064  21% /boot
tmpfs              399976          0    399976   0% /run/user/1000
/dev/sda2      3844510712 2845012388 804137660  78% /mnt/sda2
tmpfs              399976          0    399976   0% /run/user/0

So :-)

--- SoupGate-Win32 v1.05