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  usable  memory  (MemTotal and SwapTotal in /proc/meminfo). This includes the
              physical and swap memory minus a few reserved bits and kernel binary code.

       used   Used or unavailable memory (calculated as total - available)

       free   Unused memory (MemFree and SwapFree in /proc/meminfo)

       shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)

       buffers
              Memory used by kernel buffers (Buffers in /proc/meminfo)

       cache  Memory used by the page cache and slabs (Cached and SReclaimable 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, --kibi
              Display the amount of memory in kibibytes.  This is the default.

       -m, --mebi
              Display the amount of memory in mebibytes.

       -g, --gibi
              Display the amount of memory in gibibytes.

       --tebi Display the amount of memory in tebibytes.

       --pebi Display the amount of memory in pebibytes.

       --kilo Display the amount of memory in kilobytes. Implies --si.

       --mega Display the amount of memory in megabytes. Implies --si.

       --giga Display the amount of memory in gigabytes. Implies --si.

       --tera Display the amount of memory in terabytes. Implies --si.

       --peta Display the amount of memory in petabytes. Implies --si.

       -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
                Ki = kibibyte
                Mi = mebibyte
                Gi = gibibyte
                Ti = tebibyte
                Pi = pebibyte

              If  unit  is  missing,  and  you  have  exbibyte  of  RAM or swap, the number is in
              tebibytes 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 delay
              Continuously display the result delay  seconds apart.  You may actually specify any
              floating point number for delay using either . or , for decimal  point.   usleep(3)
              is used for microsecond resolution delay times.

       --si   Use  kilo,  mega,  giga  etc  (power of 1000) instead of kibi, mebi, gibi (power of
              1024).

       -t, --total
              Display a line showing the column totals.

       -v, --committed
              Display a line showing the memory commit limit and amount of  committed/uncommitted
              memory.  The total column on this line will display the memory commit limit.   This
              line is relevant if memory overcommit is disabled.

       --help Print help.

       -V, --version
              Display version information.

FILES

       /proc/meminfo
              memory information

BUGS

       The value for the shared column is  not  available  from  kernels  before  2.6.32  and  is
       displayed as zero.

       Please send bug reports to
              ⟨procps@freelists.org⟩

SEE ALSO

       ps(1), slabtop(1), top(1), vmstat(8).