free - Display amount of free and used memory in the system
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 kernel. The
information is gathered by parsing /proc/meminfo. The displayed
Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
Used memory (calculated as total - free - buffers - cache)
Unused memory (MemFree and SwapFree in /proc/meminfo)
Memory used (mostly) by tmpfs (Shmem in /proc/meminfo, available on
kernels 2.6.32, displayed as zero if not available)
Memory used by kernel buffers (Buffers in /proc/meminfo)
Memory used by the page cache and slabs (Cached and Slab in /proc/meminfo)
Sum of buffers and cache
Estimation of how much memory is available for starting
new applications, without swapping. Unlike the data
provided by the cache or free fields,
this field takes into account page cache and also that
not all reclaimable memory slabs will be reclaimed
due to items being in use (MemAvailable in /proc/meminfo, available on
kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as free)
Display the amount of memory in bytes.
Display the amount of memory in kilobytes. This is the default.
Display the amount of memory in megabytes.
Display the amount of memory in gigabytes.
Display the amount of memory in terabytes.
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.
Switch to the wide mode. The wide mode produces lines longer
than 80 characters. In this mode buffers and cache
are reported in two separate columns.
Display the result
times. Requires the
Show detailed low and high memory statistics.
Continuously display the result delay
apart. You may actually specify any floating point number for
is used for microsecond resolution delay times.