Create hard links with `ln` command
In bash you can easily create hard links with ln command. With hard links you can basically have one file with 2 different names. For example:
ln my-file.txt renamed-file.txt
Now both our txt files point to the same data on the disk, thus not duplicating the storage space needed. If you modify one file, both should be modified.
I had to use hard links when I downloaded anime with filenames which Plex didn't recognize. I wanted to keep seeding, so I just created hard links of all of the files with Plex-friendly names.