The original Linux kernel was entirely Linus Torvald's work. Also the same applies for Git. GNU Emacs was Richard Stallman entirely. Most Linux tools we use e.g

The original Linux kernel was entirely Linus Torvald's work. Also the same applies for Git. GNU Emacs was Richard Stallman entirely. Most Linux tools we use e.g. cURL, wget etc, started out as one person effort for a very long time until they caught attention. Another way to look at it: all the tools you use now are team efforts after a lone developer perfected it to a usable release, where people were largely impressed to pick it up further.