[content] Added note on history and use of linux OS. (#2410)

* [content] Added note on history and use of linux OS.

* Update content/roadmaps/114-software-architect/content/115-operations-knowledge/103-linux-unix.md

* Update content/roadmaps/114-software-architect/content/115-operations-knowledge/103-linux-unix.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/114-software-architect/content/115-operations-knowledge/103-linux-unix.md

@@ -1 +1,7 @@
-# Linux unix
+# Linux / Unix
+
+Knowledge of UNIX is a must for almost all kind of development as most of the codes that you write is most likely going to be finally deployed on a UNIX/Linux machine. Linux has been the backbone of the free and open source software movement, providing a simple and elegant operating system for almost all your needs.
+
+<BadgeLink colorScheme='blue' badgeText='Watch' href='https://www.youtube.com/watch?v=ROjZy1WbCIA'>Linux Operating System - Crash Course</BadgeLink>
+<BadgeLink colorScheme='blue' badgeText='Watch' href='https://www.coursera.org/courses?query=unix'>Coursera - Unix Courses</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.tutorialspoint.com/unix/index.htm'>Unix / Linux Tutorial</BadgeLink>