free

FREE(1)                          User Commands                         FREE(1)

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 mem-
       ory in the system, as well as the buffers and caches used by  the  ker-
       nel.  The  information  is  gathered by parsing /proc/meminfo. The dis-
       played 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 ap-
              plications, 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, avail-
              able 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  ei-
              ther  . or , for decimal point.  usleep(3) is used for microsec-
              ond 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).

procps-ng                         2018-05-31                           FREE(1)