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)

       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
                K = kibibyte
                M = mebibyte
                G = gibibyte
                T = tebibyte
                P = 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.

       --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).