I had to learn very early in my professional career that a backup can save your life.

During my studies, I was in the first or second practical phase in the company and was supposed to clean up some directories of an application on an OS/2 server. It was the administration of access rights to the branches throughout the region….

So I opened the command line and started browsing the folder structure. Finally, I found the files I wanted to delete and started typing the delete command. And sent it off...

Unfortunately, I hadn't checked again which directory I was currently in - unfortunately it was the root directory... And so a whole lot of important directories and files were irretrievably deleted.

So, now I was a poor student in the first or second semester and had to confess to my supervisors that I had just killed the access management of the entire region (around 15 branches spread across western Germany with several thousand employees).

Ugh... I could already see myself dangling from the next lamp post…

To my astonishment, the two supervisors remained completely calm - unlike me, my nerves were exhausted. First they put me on a chair so that I don't fall over. Then they took a mobile hard drive out of the closet and connected it to the server and started copying the data backed up the night before back to the server (hey, that was in the first half of the 90s, there weren't any huge backup applications for PC Server).

In any case it worked, after half an hour the server was complete and working again. All access authorizations were back and all employees were able to get into their branches and to their offices.

In any case, this incident taught me two things very early on:

1. Always DOUBLE check which directory you are in before issuing a command. I have never forgotten that to this day.
2. Always have a working backup of your data, you never know when a stupid student will come along and destroy your data. Or the next malware or ransomware strikes. Or lightning strikes. Whatever, your data is only safe with a backup - a tested backup with a tested restore, preferably with a copy on another medium in another location.

Today I no longer rely on copied files on an external hard drive, but instead make automatic backups with a professional backup application that automatically tests the backup for restoreability and copies the backup data to multiple locations.