free - display amount of free and used memory
free [-h] [-m] [-g]Options you will use
-h- Human readable.
-m, -g- Show in MiB / GiB.
-s SECONDS- Repeat every SECONDS seconds.
-w, --wide- Wide output: buffers and cache in separate columns.
Gotchas
- Look at AVAILABLE, not free. Linux deliberately fills RAM with page cache; that cache is reclaimable the instant something needs the memory. "Almost no free memory" is normal and healthy.
Taught in
Try free in a real terminal Free, in your browser - a real Ubuntu terminal to try it in, with missions that check your work.