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 kernel. 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 - buffers - cache)

       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)

       cache  Memory used by the page cache and slabs (Cached and Slab in /proc/meminfo)

       buff/cache
              Sum of buffers and cache

       available
              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)

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.

       -w, --wide
              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.

       -c, --count count
              Display the result count times.  Requires the -s option.

       -l, --lohi
              Show detailed low and high memory statistics.

       -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⟩