It's a combination of truth and fiction. The setting and overall context are based on historical facts, but the specific details and characters may have been embellished or created for the sake of the story.
In a way, Das Boot is based on true events. It incorporates real aspects of submarine operations but fictionalizes some parts to make it more engaging for the audience.
At a certain boot camp, there was a story of a drill sergeant who had a very strict and intimidating reputation. One night, during a storm, he took the trainees out for a drill. The lightning was flashing and thunder was booming. As they were running, one trainee thought he saw the drill sergeant disappear into thin air for a moment. It was so scary that the trainee thought he was seeing things due to the stress and the spooky atmosphere of the stormy night.
Yes, the 'Boot Camp' film is based on a true story. It often takes real - life experiences within the context of boot camps and portrays them on the screen.
Well, 'fear the boot bedtime stories' might be stories that use the idea of 'fear the boot' as a central theme. Maybe they are stories designed to be a bit scary or thrilling, just right for bedtime. It could be that the 'boot' represents something to be feared in these stories, like a symbol of an unknown threat or an antagonist's weapon. However, without having read them, this is all speculation.
One story is about a recruit who accidentally put his boots on the wrong feet during a morning drill. He was running all lopsided and the drill sergeant couldn't help but laugh while correcting him. It was a really funny sight as he tried to march in formation with his boots in the wrong place.