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.

       -L, --line
              Show output on a single line, often used with the -s option to show memory statistics repeatedly.

       -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).