Which command can you use to check memory usage in a Linux system?

The command that is used to check memory usage in a Linux system is 'free'. This command provides a quick snapshot of the system's memory usage, including total memory, used memory, free memory, shared memory, buffers, and cached memory. By executing the command, users can easily see how much memory is currently being utilized and how much is still available for use, making it a valuable tool for monitoring system performance.

Other tools may provide additional information or perform different functions, but 'free' is specifically designed to display the current memory state in a clear and concise manner. This makes it a go-to command for system administrators and users looking to quickly assess memory usage on a Linux system.