> Scripts offers up the entire contents of the linux operating system and this could allow you to use operating system files as partial data.

I also thought about this, but when thinking more about the argument by the challenge creator, I understood that the data in the OS doesn’t help you.

If you’re given a file with 100 bits, there are 2^100 possibilities. If you want to compress to 99 bits, there are only 2^99 possible compressed outputs. So when generating and trying to compress every 100 bit file, you’re not going to be able to compress half of them. The external data doesn’t help you unless you get to modify it after receiving the file to compress. If you can get patched merged into the Linux kernel, you could use the data, but if the data is fixed, you can’t reference the data with less data than the original file (for some cases atleast).

Edit: actually, when thinking about it: you could actually use the OS as another few bits of out of band information you get for free, which makes it possible again. If you have 8 different OS to choose from, you could use their differences to compress any file. At least theoretically, the 3 bits you gain practically probably aren’t enough to make a difference.

My decompressor:

curl ftp://path/to/original.dat

One possibility I considered is that your script could use an "apt install" to provide out of band data, you could put the information you need into the operating system from the universe repositories/your own package server.