add stuff to a1 and a3 and first part of a3

sheet08/a1.txt

@@ -1,3 +1,21 @@
 I used the simplest trick in the book. Since we have btop installed (a more advanced and pretty version of tools like top or htop), I was just able to run "btop" to get into its interface.
 
 From there, you can see which CPU the system is using in the top right. Since it's a EPYC CPU, but we only have 2 threads, it goes without saying that we're in a VM since there is no AMD EPYC CPU with only 1 core with 2 threads.
+
+Alternatively:
+
+12:55:11 leo@group-20 ~ → hostnamectl 
+ Static hostname: group-20.internal
+       Icon name: computer-vm
+         Chassis: vm 🖴
+      Machine ID: 471f9f9a79d9821160cd1849069e648a
+         Boot ID: 3621b630db6a4e0f8b8ba3269550325a
+  Virtualization: kvm
+Operating System: Ubuntu 24.04.4 LTS              
+          Kernel: Linux 6.8.0-111-generic
+    Architecture: x86-64
+ Hardware Vendor: QEMU
+  Hardware Model: Standard PC _Q35 + ICH9, 2009_
+Firmware Version: 2024.02-2ubuntu0.8
+   Firmware Date: Wed 2025-12-10
+    Firmware Age: 6month 1w

sheet08/a3.txt

@@ -0,0 +1,9 @@
+• Passing passwords via command line arguments:
+    Benefits: fast and easy to type out for quick testing.
+    Drawbacks: Highly insecure. Passwords are saved in the .bash_history and are fully visible to any other user running the `ps` command. They also leak through `docker inspect`
+• Passing passwords via an environment variable:
+    Benefits: Better than CLI arguments because they hide the secret from the ps process list.
+    Drawbacks: Still exposed. Anyone with access to docker can view them using `docker inspect`.
+• Passing passwords via a file:
+    Benefits: The secrets do not show up in the `ps` process list or in the docker inspect metadata. Access to the file on the host can also be limited using chmod.
+    Drawbacks: Leaves a plaintext file on the physical hard drive, requiring manual cleanup.