1. The Permission Headache I immediately hit a permission denied error. Instead of just using sudo every time (which is a bad habit), I learned how to add my user to the group: sudo usermod -aG docker $USER Note: You have to log out and back in for this to work!

2. Interactive vs. Detached I practiced the difference between:

   docker run -it ubuntu: Getting inside the container shell.

   docker run -d ubuntu: Letting it run in the background.

3. Useful Commands I Used Today:

   docker ps -a (to see the ghosts of containers past)

   docker images (to see what's taking up space)

   docker exec -it (better than attach for jumping back into a running container)

Conclusion: It’s not just about commands; it’s about understanding isolation. Onward to Day 2!