free flags & options

-h, --human

Display sizes in human-readable format (KB, MB, GB).

free -h

-m

Display sizes in megabytes.

free -m

-g

Display sizes in gigabytes.

free -g

-s

Continuously display output every N seconds.

free -h -s 2

free -m -s 5

-t, --total

Show a total line summing RAM and swap.

free -ht

-w, --wide

Use wide mode to separate buffers and cache into distinct columns.

free -hw