In Linux, you can use the free command to view information about the system’s memory usage. The free command displays the amount of physical memory, swap memory, and memory buffers available on the system, as well as the amount of memory that is currently being used.
To use the free command, simply open a terminal window and type the following:
free
The output will look something like this:
total used free shared buff/cache available
Mem: 8136588 5392956 789112 173528 6614620 2068420
Swap: 8191999 0 8191999
In this example, the total column shows the total amount of RAM in the system, in kilobytes. The used column shows the amount of RAM that is currently in use, the free column shows the amount of RAM that is currently unused, and the buff/cache column shows the amount of RAM that is being used as cache memory by the operating system. The available column shows the amount of RAM available for use by applications.
In addition to the free command, you can use the top command to view real-time information about memory usage, or the vmstat command to view detailed information about memory, swap, and I/O usage on the system.