free -h
The addition of the -h parameter shows the memory values in a more intuitive way.
The fields in each column are described as follows:
| field | instructions |
|---|---|
| Mem | Memory usage |
| Swap | Swap space usage |
| total | The total capacity |
| used | Have used capacity |
| free | The residual capacity |
| shared | The Shared capacity |
| buff/cache | Buff and cache capacity |
| available | Capacity that can also be used by applications |
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On Linux, SWAP functions like virtual memory on Windows. If the physical memory is insufficient, part of the hard disk space can be used as a SWAP partition (virtual memory) to solve the problem. 1.
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Buff /cache refers to buffer and page cache capacity 2, used to improve performance.
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Free means physical free memory, while available means available memory from an application perspective.
[1] What does Linux Swap do? [2] Free command in Linux