[tlug] Move the OS to a different partition?

[Thomas Blasejewicz <nyuwa@example.com>]

Good evening
In the hope everybody is safe so far! .. and we all make it through the 
storm.

I have a probably really stupid question.
On one of my "experimental machines" I have Linux Mint 19, Cinnamon 
edition, installed in a 500 GB HDD WITHOUT partitions.

IF I wanted to create a new 100GB partition, would it be possible to 
just "copy" or "move" the file system to that new partition,
designate it somehow as "/" and keep the data in /home?
Or: newly install the OS in the created 100 GB partition and then delete 
it is somehow from the resized data partition?

Somehow I am hoping Linux has some slick tricks to do that.
If not ... it is not a problem or particularly important.

Sorry for this!
Thomas