24.2. Viewing Memory Usage
24.2.1. Using the free Command
The
free command allows you to display the amount of free and used memory on the system. To do so, type the following at a shell prompt:
free
The
free command provides information about both the physical memory (Mem) and swap space (Swap). It displays the total amount of memory (total), as well as the amount of memory that is in use (used), free (free), shared (shared), in kernel buffers (buffers), and cached (cached). For example:
~]$ free
total used free shared buffers cached
Mem: 760752 661332 99420 0 6476 317200
-/+ buffers/cache: 337656 423096
Swap: 1540088 283652 1256436
By default,
free displays the values in kilobytes. To display the values in megabytes, supply the -m command-line option:
free-m
For instance:
~]$ free -m
total used free shared buffers cached
Mem: 742 646 96 0 6 309
-/+ buffers/cache: 330 412
Swap: 1503 276 1227
For a complete list of available command-line options, see the free(1) manual page.
