FREE(1) User Commands FREE(1)
NAME
free - Display amount of free and used memory in the system
SYNOPSIS
free [options]
DESCRIPTION
free displays the total amount of free and used physical and swap memory in the system, as well as the buffers and caches used by the ker-
nel. The information is gathered by parsing /proc/meminfo. The displayed columns are:
total Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
used Used memory (calculated as total - free)
free Unused memory (MemFree and SwapFree in /proc/meminfo)
shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo, available on kernels 2.6.32, displayed as zero if not available)
buffers
Memory used by kernel buffers (Buffers in /proc/meminfo)
cached Memory used by the page cache (calculated as Cached - Shmem in /proc/meminfo - the Cached value is actually the sum of page cache
and tmpfs memory)
OPTIONS
-b, --bytes
Display the amount of memory in bytes.
-k, --kilo
Display the amount of memory in kilobytes. This is the default.
-m, --mega
Display the amount of memory in megabytes.
-g, --giga
Display the amount of memory in gigabytes.
--tera Display the amount of memory in terabytes.
-h, --human
Show all output fields automatically scaled to shortest three digit unit and display the units of print out. Following units are
used.
B = bytes
K = kilos
M = megas
G = gigas
T = teras
If unit is missing, and you have petabyte of RAM or swap, the number is in terabytes and columns might not be aligned with header.
-c, --count count
Display the result count times. Requires the -s option.
-l, --lohi
Show detailed low and high memory statistics.
-o, --old
Display the output in old format, the only difference being this option will disable the display of the "buffer adjusted" line.
-s, --seconds seconds
Continuously display the result delay seconds apart. You may actually specify any floating point number for delay, usleep(3) is
used for microsecond resolution delay times.
--si Use power of 1000 not 1024.
-t, --total
Display a line showing the column totals.
--help Print help.
-V, --version
Display version information.
FILES
/proc/meminfo
memory information
SEE ALSO
ps(1), slabtop(1), top(1), vmstat(8).
AUTHORS
Written by Brian Edmonds.
REPORTING BUGS
Please send bug reports to <procps@freelists.org>
procps-ng September 2011 FREE(1)
