Added information about df command (#2413)

* Added information about df command

* Update content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/138-df.md

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

content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/138-df.md

@@ -1 +1,14 @@
-# Df
+# df
+
+`df` is Linux/Unix command used to show the disk usage & information. df is an abbreviation for `disk free`. df displays the amount of disk space available for a particular file system partition. If no name is given, it shows the space available on all currently mounted partitions.
+
+The basic syntax of the command is like the following:
+`df <mounted partition name>`
+
+Example usage: 
+`df /tmp` to show the available space of /tmp partition.
+or `df` to show information about the partitions of the whole system.
+
+<ResourceGroupTitle>Useful Links</ResourceGroupTitle>
+<BadgeLink colorScheme='blue' badgeText='Man page' href='https://linux.die.net/man/1/df'>df man page</BadgeLink>
+<BadgeLink colorScheme='blue' badgeText='Tutorial' href='https://www.geeksforgeeks.org/df-command-linux-examples/'>df command with examples</BadgeLink>