It’s impossible to have a good understanding of the way RAM is used in your Linux box without an appreciation of the state of your swap space. RELATED: How to Use the free Command on Linux The vmstat Command You can also use the following nifty trick we tweaked from one of our readers to see the percentage of swap space that is used: free -m | grep Swap | awk '' Free: The amount of remaining (unused) swap space.Used: The amount of swap space that’s in use.Total: The size of the swap partition or file.The Swap columns contain the following information: Available: This is an estimate of the memory that’s available to service memory requests from applications and any other operational software on your computer.This can be released quickly by the kernel if required. Buff/cache: Amount of memory used for buffers and cache.Shared: Amount of memory used by the tmpfs file systems.Used: The sum of Free+Buffers+Cache subtracted from the total amount.Total: The total amount of physical RAM on this computer.The Mem columns contain the following information:

This is the output we get: total used free shared buff/cache available

Linux display memory usage