1FREE(1)                          User Commands                         FREE(1)
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NAME

6       free - Display amount of free and used memory in the system
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SYNOPSIS

9       free [options]
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DESCRIPTION

12       free  displays the total amount of free and used physical and swap mem‐
13       ory in the system, as well as the buffers and caches used by  the  ker‐
14       nel.  The  information  is  gathered by parsing /proc/meminfo. The dis‐
15       played columns are:
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17       total  Total installed memory (MemTotal and SwapTotal in /proc/meminfo)
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19       used   Used memory (calculated as total - free - buffers - cache)
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21       free   Unused memory (MemFree and SwapFree in /proc/meminfo)
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23       shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo, available
24              on kernels 2.6.32, displayed as zero if not available)
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26       buffers
27              Memory used by kernel buffers (Buffers in /proc/meminfo)
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29       cache  Memory  used  by  the  page  cache and slabs (Cached and Slab in
30              /proc/meminfo)
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32       buff/cache
33              Sum of buffers and cache
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35       available
36              Estimation of how much memory  is  available  for  starting  new
37              applications,  without swapping. Unlike the data provided by the
38              cache or free fields, this field takes into account  page  cache
39              and also that not all reclaimable memory slabs will be reclaimed
40              due to items being in use (MemAvailable in /proc/meminfo, avail‐
41              able on kernels 3.14, emulated on kernels 2.6.27+, otherwise the
42              same as free)
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OPTIONS

45       -b, --bytes
46              Display the amount of memory in bytes.
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48       -k, --kilo
49              Display the amount of memory in kilobytes.  This is the default.
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51       -m, --mega
52              Display the amount of memory in megabytes.
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54       -g, --giga
55              Display the amount of memory in gigabytes.
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57       --tera Display the amount of memory in terabytes.
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59       --peta Display the amount of memory in petabytes.
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61       -h, --human
62              Show all output fields automatically scaled  to  shortest  three
63              digit  unit and display the units of print out.  Following units
64              are used.
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66                B = bytes
67                K = kilos
68                M = megas
69                G = gigas
70                T = teras
71                P = petas
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73              If unit is missing, and you have exabyte of  RAM  or  swap,  the
74              number  is  in  terabytes  and columns might not be aligned with
75              header.
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77       -w, --wide
78              Switch to the wide mode. The wide  mode  produces  lines  longer
79              than  80 characters. In this mode buffers and cache are reported
80              in two separate columns.
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82       -c, --count count
83              Display the result count times.  Requires the -s option.
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85       -l, --lohi
86              Show detailed low and high memory statistics.
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88       -s, --seconds seconds
89              Continuously display the result delay seconds  apart.   You  may
90              actually  specify any floating point number for delay, usleep(3)
91              is used for microsecond resolution delay times.
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93       --si   Use power of 1000 not 1024.
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95       -t, --total
96              Display a line showing the column totals.
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98       --help Print help.
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100       -V, --version
101              Display version information.
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FILES

104       /proc/meminfo
105              memory information
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SEE ALSO

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

111       Written by Brian Edmonds.
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REPORTING BUGS

114       Please send bug reports to ⟨procps@freelists.org⟩
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118procps-ng                          July 2014                           FREE(1)
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