"Gzip" compresses to smaller files than the "compress" command and so is used for almost all compressed files on Unix and Unix-like systems.
I have a problem with the adverb "so" there. I'm not sure if I understand the semantics of its usage in this example very well. "so" when used as an adverb like that typically means "in the manner of", but it doesn't really sound like that's the case here. And the "gzip" utility is used in this manner of compressing to smaller files than the standard "compress" command for all files that need compression in Unix? Hmm... As I said, I'm not sure if my interpretation is correct. What's your thoughts?