No he didn’t. He built a proof of concept demo in 7 days then handed it off to other maintainers to code for real. I’m not sure why this myth keeps getting repeated. Linus himself clarifies this in every interview about git.
His main contributions were his ideas.
1) The distributed model, that doesn’t need to dial the internet.
2) The core data structures. For instance, how git stores snapshots for files changes in a commit. Other tools used diff approaches which made rewinding, branch switching, and diffing super slow.
Those two ideas are important and influenced git deeply, but he didn’t code the thing, and definitely not in 7 days!
Those were not his ideas. Before Git, the Linux kernel team was using BitKeeper for DVCS (and other DVCS implementations like Perforce existed as well). Git was created as a BitKeeper replacement after a fight erupted between Andrew Tridgell (who was accused of trying to reverse engineer BitKeeper in violation of its license) and Larry McVoy (the author of BitKeeper).
https://graphite.com/blog/bitkeeper-linux-story-of-git-creat...
You may find this 10-year-old thread on HN enlightening, too: https://news.ycombinator.com/item?id=11667494
That's just being pedantic for the sake of it.
Git is decades old. Of course, there are tons of contributions after the first 10 days. Everyone knows that.
He started it and built the first working version.
He did what needed to be done. Linux similarly has thousands of contributors and Linus's personal "code contribution" is almost negligible these days. But code doesn't matter. Literally anyone can generate thousands of lines of code that will flip bits all day long. What matters is some combination of the following: a vision, respect from peers earned with technical brilliance, audaciousness, tenacity, energy, dedication etc. This is what makes Linus special. Not his ability to bash on a keyboard all day long.
The point was only that Linus didn't build git in 8 days and alone.