# free

## NAME



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


## SYNOPSIS



           **free**[_option_ ...]
    


## 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 usable memory (MemTotal and SwapTotal in
                  /proc/meminfo). This includes the physical and swap memory
                  minus a few reserved bits and kernel binary code.
    
           **used** Used or unavailable memory (calculated as **total** -
                  **available**)
    
           **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.
    
           **-L** , **--line**
                  Show output on a single line, often used with the **-s** option
                  to show memory statistics repeatedly.
    
           **-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.
    
           **-v** , **--committed**
                  Display a line showing the memory commit limit and amount
                  of committed/uncommitted memory. The **total** column on this
                  line will display the memory commit limit.   This line is
                  relevant if memory overcommit is disabled.
    
           **--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⟩.
    


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