Which option is used with the 'free' command to display memory in human-readable format?

The option used with the 'free' command to display memory in a human-readable format is indeed the '-h' option. When this option is utilized, the output of the command is adjusted to automatically use the most appropriate size units (such as kilobytes, megabytes, or gigabytes) based on the amount of memory being reported. This makes it easier for users to understand the output at a glance, as the numbers are converted into a format that is more relatable, avoiding confusion caused by raw byte counts.

This human-readable format is particularly useful when monitoring system memory usage, as it provides clarity without requiring users to perform manual conversions. The command could output something like "1.2G" for gigabytes or "256M" for megabytes, thereby enhancing the ease of interpretation of the memory stats provided by the 'free' command.