Useful Commands

Commands that are useful to know, might come handy some time.

free: Displays the memory details, i.e memory free and used etc. Also shows the memory usage of swap. Useful when you want to see how much of your RAM is being used by some application.

vmstat: Gives statistics of the virtual memory usage. Similar to "free" but a little more detailed. We can also get statistics for a period of time continously for eg

vmstat 1 10

would print the current statistics for 10 seconds.

lsof :  Lists all the open files. Including different system files opened by processes.