Keeping tabs on your storage is always important, as no one enjoys getting a call in the middle of the night that a server is having an issue, much less something that could've been avoided, such as a filesystem growing too close to being full. Managing storage on Linux systems is easy once you master the related tools, the most useful of which I'll go over in this section. In particular, we'll answer the question "what's eating all my free space?" and I'll provide you with some examples of how to find out.
First, the df command. This command is likely always going to be your starting point in situations where you don't already know which volume is becoming full. When executed, it gives you a high-level overview, so it's not necessarily useful when you want to figure out who or what in particular is hogging all your space. However, when you just want to list all your mounted volumes and see how much space is left on each, df fits the bill. By default, it shows you the information...