man > free(1)

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 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
                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.

       --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 AT freelists.org⟩

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



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