Add terminal usage resources

* update 100-terminal-usage.md

* Update content/roadmaps/101-backend/content/102-os-general-knowledge/100-terminal-usage.md

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

content/roadmaps/101-backend/content/102-os-general-knowledge/100-terminal-usage.md

@@ -1 +1,6 @@
 # Terminal usage
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+Terminals, also known as command lines or consoles, allow us to accomplish and automate tasks on a computer without the use of a graphical user interface.
+
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://developer.mozilla.org/en-US/docs/Learn/Tools_and_testing/Understanding_client-side_tools/Command_line'>Command line crash course</BadgeLink>
+<BadgeLink colorScheme='green' badgeText='Course' href='https://www.youtube.com/watch?v=jDINUSK7rXE'>Basic Terminal Usage - Cheat Sheet to make the command line EASY</BadgeLink>