I recently came across a very interesting history of the early evolution of the Unix OS and some of these core utils during the 1970s and early 1980s: https://

I recently came across a very interesting history of the early evolution of the Unix OS and some of these core utils during the 1970s and early 1980s: https://www.cs.dartmouth.edu/~doug/reader.pdf https://www.cs.dartmouth.edu/~doug/reader.pdf Lots of cool details about stuff like the gradual migration of the kernel from 100% assembly C and the origin stories of a lot of these ubiquitous utility programs like cp, ls, etc.