Understanding the free Command

Basic Usage of free

The free command is used to display information about system memory usage, including total, used, free, shared, buffer/cache, and available memory. This command helps in monitoring memory consumption on a Linux system.

Options Available with free

-h (Human-readable)

Display memory sizes in a human-readable format (e.g., KB, MB, GB):

-b (Bytes)

Display memory sizes in bytes:

-k (Kilobytes)

Display memory sizes in kilobytes (default):

-m (Megabytes)

Display memory sizes in megabytes:

-g (Gigabytes)

Display memory sizes in gigabytes:

-s seconds (Continuous Mode)

Display memory usage at regular intervals in seconds:

-t (Total)

Display a line showing the total memory usage:

--help

Display help information for the command:

--version

Display the version information of the command:

Examples of free Command

Display Memory Usage Summary

This command displays the total, used, free, shared, buffer/cache, and available memory.

Display Human-readable Memory Usage

This command shows memory usage in a more readable format with units (KB, MB, GB).

Display Memory Usage Every 5 Seconds

This command updates the memory usage display every 5 seconds.

Understanding Memory Usage Information

The output of the free command typically includes the following columns:

• Total: Total amount of memory available.
• Used: Memory currently in use by the system.
• Free: Memory that is not being used at all.
• Shared: Memory that is shared between processes.
• Buffer/Cache: Memory used by the kernel buffers and caches.
• Available: Estimated amount of memory available for starting new applications.

Summary of Options