If you have several servers to maintain like I do, at some point you’ll want to know how old exactly an installation of Debian (or another flavor or Linux) has gotten since you last wiped it clean…
So how do you check the install date?
I found the easiest way was to simply check the date of the lost+found folder. This folder is created at installation time and basically never removed after that. So I just go with:
ls -l /home/
and look at the date for lost+found .