# FREE - man - [phpMan]

> **TLDR:** Display amount of free and used memory in the system.
>
- Display system memory:
  `free`
- Display memory in Bytes/KB/MB/GB:
  `free -{{b|k|m|g}}`
- Display memory in human-readable units:
  `free {{-h|--human}}`
- Refresh the output every 2 seconds:
  `free {{-s|--seconds}} 2`

*Source: tldr-pages*

---

[_FREE_(1)](https://www.chedong.com/phpMan.php/man/FREE/1/markdown)                                     User Commands                                    [_FREE_(1)](https://www.chedong.com/phpMan.php/man/FREE/1/markdown)

## 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 usable memory (MemTotal and SwapTotal in /proc/meminfo). This includes the phys‐
              ical 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 _
              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 _
              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)](https://www.chedong.com/phpMan.php/man/usleep/3/markdown)  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>](<procps@freelists.org>)

## SEE ALSO
       [**ps**(1)](https://www.chedong.com/phpMan.php/man/ps/1/markdown), [**slabtop**(1)](https://www.chedong.com/phpMan.php/man/slabtop/1/markdown), [**top**(1)](https://www.chedong.com/phpMan.php/man/top/1/markdown), [**vmstat**(8)](https://www.chedong.com/phpMan.php/man/vmstat/8/markdown).

procps-ng                                    2023-05-02                                      [_FREE_(1)](https://www.chedong.com/phpMan.php/man/FREE/1/markdown)