The free command is a Linux utility used to display the amount of free and used RAM memory in the system in kilobytes (KB)at the current moment. If you prefer to view instead in megabytes (MB) you can use the –m option. Typing “free” or “free –m” on the command line you would get an output like this;
This output displays a machine with 1075MB of RAM memory and a swap partition of 1096MB. And there is 233MB of stale data buffered and stored in the “cache” memory. When there is need for memory the system converts the cache (buffered) memory for use.
It’s a common system management procedure to always monitor your computer memory (RAM) usage, a limited memory would be obvious by the computer system becoming sluggish. The free command is just one among many other commands that is used for memory monitoring in Linux.