Individual web pages here, entire web sites go on the web sites page.
On the Early History and Impact of Unix, Ronda Hauben, part of her larger work Netizens: An Anthology
Twenty Years of Berkeley Unix: From AT&T-Owned to Freely Redistributable, Marshall Kirk McKusick, from Open Sources: Voices from the Open Source Revolution
A short history on the origins of grep by Benjamin Rualthanzauva.