How to Check Memory Usage in Linux (free -m)

free displays the amount of free and used physical memory (RAM) and swap space on the system.

Key points

• The -m flag displays sizes in megabytes instead of raw bytes, making the output easier to read
• The "available" column is the most reliable estimate of memory actually available for new processes
• Low "free" memory alone isn't necessarily a problem — Linux uses spare RAM for disk caching, which is reclaimed automatically when needed

Example

free -mh