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 usable memory (MemTotal and SwapTotal  in  /proc/meminfo).
18              This  includes the physical and swap memory minus a few reserved
19              bits and kernel binary code.
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21       used   Used or unavailable memory (calculated as total - available)
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23       free   Unused memory (MemFree and SwapFree in /proc/meminfo)
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25       shared Memory used (mostly) by tmpfs (Shmem in /proc/meminfo)
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27       buffers
28              Memory used by kernel buffers (Buffers in /proc/meminfo)
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30       cache  Memory used by the page cache and slabs (Cached and SReclaimable
31              in /proc/meminfo)
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33       buff/cache
34              Sum of buffers and cache
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36       available
37              Estimation  of how much memory is available for starting new ap‐
38              plications, without swapping. Unlike the data  provided  by  the
39              cache  or  free fields, this field takes into account page cache
40              and also that not all reclaimable memory slabs will be reclaimed
41              due to items being in use (MemAvailable in /proc/meminfo, avail‐
42              able on kernels 3.14, emulated on kernels 2.6.27+, otherwise the
43              same as free)
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OPTIONS

46       -b, --bytes
47              Display the amount of memory in bytes.
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49       -k, --kibi
50              Display the amount of memory in kibibytes.  This is the default.
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52       -m, --mebi
53              Display the amount of memory in mebibytes.
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55       -g, --gibi
56              Display the amount of memory in gibibytes.
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58       --tebi Display the amount of memory in tebibytes.
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60       --pebi Display the amount of memory in pebibytes.
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62       --kilo Display the amount of memory in kilobytes. Implies --si.
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64       --mega Display the amount of memory in megabytes. Implies --si.
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66       --giga Display the amount of memory in gigabytes. Implies --si.
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68       --tera Display the amount of memory in terabytes. Implies --si.
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70       --peta Display the amount of memory in petabytes. Implies --si.
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72       -h, --human
73              Show  all  output  fields automatically scaled to shortest three
74              digit unit and display the units of print out.  Following  units
75              are used.
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77                B = bytes
78                Ki = kibibyte
79                Mi = mebibyte
80                Gi = gibibyte
81                Ti = tebibyte
82                Pi = pebibyte
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84              If  unit  is  missing, and you have exbibyte of RAM or swap, the
85              number is in tebibytes and columns might  not  be  aligned  with
86              header.
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88       -w, --wide
89              Switch  to  the  wide  mode. The wide mode produces lines longer
90              than 80 characters. In this mode buffers and cache are  reported
91              in two separate columns.
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93       -c, --count count
94              Display the result count times.  Requires the -s option.
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96       -l, --lohi
97              Show detailed low and high memory statistics.
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99       -s, --seconds delay
100              Continuously  display  the result delay  seconds apart.  You may
101              actually specify any floating point number for delay  using  ei‐
102              ther  . or , for decimal point.  usleep(3) is used for microsec‐
103              ond resolution delay times.
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105       --si   Use kilo, mega, giga etc (power of 1000) instead of kibi,  mebi,
106              gibi (power of 1024).
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108       -t, --total
109              Display a line showing the column totals.
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111       -v, --committed
112              Display  a  line  showing  the memory commit limit and amount of
113              committed/uncommitted memory. The total column on this line will
114              display the memory commit limit.   This line is relevant if mem‐
115              ory overcommit is disabled.
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117       --help Print help.
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119       -V, --version
120              Display version information.
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FILES

123       /proc/meminfo
124              memory information
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BUGS

127       The value for the shared column is not available  from  kernels  before
128       2.6.32 and is displayed as zero.
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130       Please send bug reports to
131              ⟨procps@freelists.org⟩
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SEE ALSO

134       ps(1), slabtop(1), top(1), vmstat(8).
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138procps-ng                         2023-01-16                           FREE(1)