free — Report the free memory on the system.

free [−b | −k | −m | −p] [−s delay] [−vV]

DESCRIPTION

free displays the total amount of free and used physical memory in the system. free understands the following options:

Represent the memory in bytes

−k
Represent the memory in kilobytes (default)

−m
Represent the memory in megabytes

−p
Represent the memory in number of pages

−s delay
Print a report every delay seconds. Delay may be a floating-point value; usleep(3) is used for microsecond precision delay times.

−v
Include pagein and pageout statistics in the output.

−V
Prints version information and exits.

DIAGNOSTICS

The amount of memory in use is defined by the number of pages active, inactive and wired, multiplied by the page size of course. The total memory is worked out by adding the in-use memory to the free memory - experiment shows this works.

ps(1), top(1), vm_stat(1)

free occasionally exhibits a rounding error, leading the total amount of RAM to be off by one (chosen unit of display).

free first appeared in Linux. The Darwin version was created by Graham Lee <leeg@teaching.physics.ox.ac.uk>.

Darwin August 21, 2006 Darwin